- DCXHTMLGuidelines/2007-07-27

Expressing Dublin Core metadata using HTML/XHTML meta and link elements

This document is part of the DC Architecture Wiki.

IMPORTANT: Do not cite materials in this Wiki other than for the purposes of collaborating on document creation. This Wiki is intended to be used to work on draft copies of documents. Finished documents will be published, in a persistent and citable form, on the dublincore.org Web site (or elsewhere in some cases).

Title:	Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Creator:	Pete Johnston, Eduserv Foundation <pete.johnston@eduserv.org.uk>
Creator:	Andy Powell, Eduserv Foundation <andy.powell@eduserv.org.uk>
Date Issued:	2007-07-22
Identifier:	http://dublincore.org/architecturewiki/DCXHTMLGuidelines/2007-07-27
Replaces:	http://dublincore.org/documents/2003/11/30/dcq-html/
Is Replaced By:	Not applicable
Latest Version:	http://dublincore.org/architecturewiki/DCXHTMLGuidelines
Description of Document:	This document describes how a Dublin Core metadata description set can be encoded in HTML/XHTML <meta> and <link> elements.

Expressing Dublin Core metadata using HTML/XHTML meta and link elements

1. Introduction
2. The DCMI Abstract Model and DC-HTML
3. Features of the DC-HTML Syntax

3.1 URIs in DC-HTML

3.1.1 URI references
3.1.2 URIs, DC-HTML Prefixed Names and Namespace Declarations

4. The DC-HTML Profile

4.1 The Profile Attribute Value
4.2 DC-HTML Namespace Declarations
4.3 Encoding a Description Set
4.4 Encoding a Description

4.4.1 The Described Resource URI

4.5 Encoding a Statement

4.5.1 Encoding a Statement containing a Literal Value Surrogate

4.5.1.1. The Property URI
4.5.1.2 Encoding a Literal Value Surrogate

4.5.2 Encoding a Statement containing a Non-Literal Value Surrogate

4.5.2.1. The Property URI
4.4.2.2 Encoding a Non-Literal Value Surrogate

Appendix A. DC-TEXT Representation of Examples

A.1 Examples 1 & 2
A.2 Example 3 & 4
A.3 Example 5 & 6
A.4 Example 7 & 8
A.5 Examples 9 & 10
A.6 Examples 11 & 12
A.7 Examples 13 & 14
A.8 Examples 15 & 16
A.9 Examples 17 & 18
A.10 Examples 19 & 20
A.11 Examples 21 & 22
A.12 Examples 23 & 24
A.13 Examples 25 & 26
A.14 Examples 27 & 28
A.15 Examples 29 & 30

References
Changes in this version

1. Introduction

This document specifies a set of conventions by which a DC metadata description set can be can be represnted within an HTML/XHTML Web page using HTML/XHTML elements. Formally it defines a metadata profile for HTML and XHTML.

The "Description Set Model" of the DCMI Abstract Model [DCAM] describes the constructs that make up a DC metadata description set. In order to represent a DC metadata description set in an X/HTML document those constructs have to be represented as components in that HTML/XHTML document, i.e. as HTML/XHTML elements and attributes and as element content and attribute values.

2. The DCMI Abstract Model and DC-HTML

According to the "Description Set Model" of the DCMI Abstract Model [DCAM], a DC description set has the following structure:

a description set is made up of one or more descriptions
a description is made up of

zero or one described resource URI and
one or more statements

a statement is made up of

exactly one property URI and
exactly one value surrogate

a value surrogate is either a literal value surrogate or a non-literal value surrogate

a literal value surrogate is made up of exactly one value string
a non-literal value surrogate is made up of

zero or one value URIs
zero or one vocabulary encoding scheme URIs
zero or more value strings

a value string is either a plain value string or a typed value string

a plain value string may be associated with a value string language
a typed value string is associated with a syntax encoding scheme URI

a non-literal value may be described by another description

The conventions described in this document implement the following subset of the DCAM "description set model".

a description set is made up of one description
a description is made up of

one described resource URI and
one or more statements

a statement is made up of

exactly one property URI and
exactly one value surrogate

a value surrogate is either a literal value surrogate or a non-literal value surrogate

a literal value surrogate is made up of

exactly one value string

a non-literal value surrogate is made up of

exactly one value URI
zero or one plain value strings

a value string is either a plain value string or a typed value string

a plain value string may be associated with a value string language
a typed value string is associated with a syntax encoding scheme URI

i.e. the conventions here support a description set containing a single description, and a maximum of one value string per value surrogate. In a non-literal value surrogate, a value URI must be provided and a value string must be a plain value string. The provision of a vocabulary encoding scheme URI is not supported.

3. Features of the DC-HTML Syntax

3.1 URIs in DC-HTML

The DCAM uses Uniform Resource Identifiers (URIs) [RFC3896] to refer both to the resources described and to metadata terms (properties, classes, vocabulary encoding schemes and syntax encoding schemes).

In the DC-HTML profile, those URIs are encoded as X/HTML attribute values. Later sections of this document describe the use of those different X/HTML attributes in detail. The purpose of this section is to make some general points about the representation of these URIs in DC-HTML.

3.1.1 URI references

In the DC-HTML profile, value URIs are encoded as URI references, used as X/HTML attribute values. A URI reference is either a URI or a relative reference [RFC3896].

The URI may be represented in full. The following example shows a value URI as the value of the href attribute:

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
   "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" >
<link rel="DCTERMS.subject" href="http://example.org/topics/archives" >
</head>
<body>
</body>
</html>

Example 1: URI as attribute value (HTML)

<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
     "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" />
<link rel="DCTERMS.subject" href="http://example.org/topics/archives" />
</head>
<body>
</body>
</html>

Example 2: URI as attribute value (XHTML)

For all of the attributes in DC-HTML which have URIs as values, the value may also be a relative reference. The relative reference is resolved relative to a base URI, obtained either from the value of an xml:base attribute or from the URI of the document itself. In the following example, the value of the href attribute is a relative reference. It is resolved relative to the base URI provided by the href attribute of the base element to obtain a target URI of http://example.org/docs/doc123:

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
   "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<base href="http://example.org/docs/" >
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" >
<link rel="DCTERMS.isReferencedBy" href="doc123" >
</head>
<body>
</body>
</html>

Example 3: Relative reference as attribute value (HTML)

<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
     "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<base href="http://example.org/docs/" >
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" />
<link rel="DCTERMS.isReferencedBy" href="doc123" />
</head>
<body>
</body>
</html>

Example 4: Relative reference as attribute value (XHTML)

3.1.2 URIs, DC-HTML Prefixed Names and Namespace Declarations

In DC-HTML, property URIs and syntax encoding scheme URIs are represented as DC-HTML Prefixed Names.

A DC-HTML Prefixed Name is an abbreviation for a URI used in the DC-HTML format. A DC-HTML Prefixed Name consists of a "prefix" followed by a period (".") and a "local name".

The "prefix" in a DC-HTML Prefixed Name is associated with a "namespace URI" using a namespace declaration, made using a Namespace Declaration Element (see the section on Namespace Declarations below). The URI represented by the DC-HTML Prefixed Name is determined by concatenating the "namespace URI" with which the prefix is associated and the "local name".

If the prefix used in a DC-HTML Prefixed Name has not been associated with a URI in a namespace declaration, it is an error and no URI can be generated for that DC-HTML Prefixed Name. If the prefix has been associated with multiple URIs (though multiple namespace declarations) then the prefix is associated with the namespace URI specified in the latest declaration in the DC-HTML instance.

For a software application that is "encoding" a description set by generating a DC-HTML instance, a DC-HTML Prefixed Name to represent a URI is determined by

dividing the URI into a pair consisting of a local name (the trailing characters of the URI, subject to the lexical constraints described above) and a namespace URI (the preceding part of the URI), and
providing a Namespace Declaration element for this namespace URI (using a prefix in the namespace declaration and in the DC-HTML Prefixed Name).

Note that this means for a single URI there is more than one possible DC-HTML Prefixed Name representation. For example, the URI http://purl.org/dc/terms/title might be represented using any of the following (namespace URI, local name) pairs:

{http://purl.org/dc/terms/}, title
{http://purl.org/dc/terms/t}, itle
{http://purl.org/dc/terms/ti}, tle
{http://purl.org/dc/terms/tit}, le
{http://purl.org/dc/terms/titl}, e

Communities typically decide on a convention for the DC-HTML Prefixed Name to be used for a URI, particularly for the URIs of terms (properties, classes, vocabulary encoding schemes and syntax encoding schemes), but in theory any of these four forms could be deployed without changing the interpretation of the instance. For all DCMI terms, the convention used by the DCMI community is to split the term URI into an expanded name at the right-most '/' (forward slash) character (as per the first example above). Also, the characters used for the prefix in a DC-HTML Prefixed Name are not significant, but communities often adopt a convention on the common use of a prefix to facilitate human readability.

The following examples shows a namespace declaration and the use of a DC-HTML Prefixed Name for the value of the name attribute of the meta element:

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
   "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" >
<meta name="DCTERMS.title" content="Services to Government" >
</head>
<body>
</body>
</html>

Example 5: DC-HTML Prefixed Name as attribute value (HTML)

<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
     "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" />
<meta name="DCTERMS.title" content="Services to Government" />
</head>
<body>
</body>
</html>

Example 6: DC-HTML Prefixed Name as attribute value (XHTML)

4. The DC-HTML Profile

4.1 The Profile Attribute Value

Where these conventions are used to represent a DC metadata description set in an X/HTML document, the value of the profile attribute of the X/HTML head element must include the URI of this X/HTML metadata profile `http://dublincore.org/documents/2007/07/27/dc-html/

4.2 DC-HTML Namespace Declarations

A DC-HTML namespace declaration associates a URI with a prefix, so that when that prefix is used in a DC-HTML Prefixed Name, that URI is used as a "namespace URI". A namespace declaration is made using the X/HTML link element and a specific convention for the value of the rel attribute. In the DC-HTML profile, an X/HTML link element of which the rel attribute has a value beginning with the characters schema. represents a namespace declaration.

The DC-HTML namespace declaration must include:

a prefix, represented by part of the value of the rel attribute of the X/HTML link element following the characters schema.
a namespace URI, represented by the value of the href attribute of the X/HTML link element

In the following example, declarations are provided for two prefixes, each of which is used subsequently in a DC-HTML Prefixed Name.

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
   "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" >
<link rel="schema.MARCREL" href="http://www.loc.gov/loc.terms/relators/" >
<meta name="DCTERMS.title" content="Services to Government" >
<link rel="MARCREL.EDT" href="http://example.org/agents/DeptOfObfuscation" >
</head>
<body>
</body>
</html>

Example 7: The Namespace Declaration (HTML)

<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
     "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" />
<link rel="schema.MARCREL" href="http://www.loc.gov/loc.terms/relators/" />
<meta name="DCTERMS.title" content="Services to Government" />
<link rel="MARCREL.EDT" href="http://example.org/agents/DeptOfObfuscation" />
</head>
<body>
</body>
</html>

Example 8: The Namespace Declaration (XHTML)

4.3 Encoding a Description Set

A description set is made up of one description.

In the DC-HTML profile, the description set is not explicitly represented, but the statements represented constitute a single description within a description set.

4.4 Encoding a Description

A description is a set of one or more statements about a resource.

In the DC-HTML profile, the description is not explicitly represented, but the statements represented constitute a single description.

4.4.1 The Described Resource URI

A description has an associated described resource URI.

In the DC-HTML profile-Full, the described resource URI is the URI of the X/HTML document

4.5 Encoding a Statement

A description is made up of one or more statements.

In the DC-HTML profile, each statement is represented as either an X/HTML meta element or an X/HTML link element. The choice of X/HTML element depends on whether the statement contains a literal value surrogate or a non-literal value surrogate.

The examples below show a description consisting of two statements.

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
   "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" >
<meta name="DCTERMS.title" content="Services to Government" >
<link rel="DCTERMS.subject" href="http://example.org/topics/archives" title="Archives" >
</head>
<body>
</body>
</html>

Example 9: Statements as meta and link elements (HTML)

<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
     "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" />
<meta name="DCTERMS.title" content="Services to Government" />
<link rel="DCTERMS.subject" href="http://example.org/topics/archives" title="Archives" />
</head>
<body>
</body>
</html>

Example 10: Statements as meta and link elements (XHTML)

4.5.1 Encoding a Statement containing a Literal Value Surrogate

In the DC-HTML profile, each statement containing a literal values surrogate is represented as an X/HTML meta element.

4.5.1.1. The Property URI

A statement must contain exactly one property URI.

In the DC-HTML profile, a property URI in a statement containing a literal values surrogate is represented as a DC-HTML Prefixed Name which is the value of the name attribute of an X/HTML meta element.

The examples below shows a description consisting of a single statement where the property URI is http://purl.org/dc/terms/title.

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
   "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" >
<meta name="DCTERMS.title" content="Services to Government" >
</head>
<body>
</body>
</html>

Example 11: The Property URI as the value of the name Attribute (HTML)

<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
     "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" />
<meta name="DCTERMS.title" content="Services to Government" />
</head>
<body>
</body>
</html>

Example 12: The Property URI as the value of the name Attribute (XHTML)

4.5.1.2 Encoding a Literal Value Surrogate

A literal value surrogate is made up of exactly one value string.

In the DC-HTML profile, a value string within a literal values surrogate is represented by the combination of the values of several attributes of an X/HTML meta element.

A value string is either a plain value string or a typed value string.

A plain value string may be associated with a value string language.

In the DC-HTML profile, the string itself is represented as the value of the content attribute of an X/HTML meta element, and a value string language is represented by the value of the lang (HTML) or xml:lang (XHTML) attribute of the meta element.

The examples below shows a description consisting of a single statement with a literal value surrogate made up of a plain value string with no value string language.

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
   "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" >
<meta name="DCTERMS.title" content="Services to Government" >
</head>
<body>
</body>
</html>

Example 13: Literal Value Surrogate Plain Value String as value of content Attribute (HTML)

<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
     "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" />
<meta name="DCTERMS.title" content="Services to Government" />
</head>
<body>
</body>
</html>

Example 14: Literal Value Surrogate Plain Value String as value of content Attribute (XHTML)

The examples below shows a description consisting of a single statement with a literal value surrogate made up of a plain value string which includes a value string language.

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
   "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" >
<meta name="DCTERMS.title" lang="en" content="Services to Government" >
</head>
<body>
</body>
</html>

Example 15: Literal Value Surrogate Plain Value String with Value String Language (HTML)

<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
     "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" />
<meta name="DCTERMS.title" xml:lang="en" content="Services to Government" />
</head>
<body>
</body>
</html>

Example 16: Literal Value Surrogate Plain Value String with Value String Language (XHTML)

A typed value string is associated with a syntax encoding scheme URI.

In the DC-HTML profile, the string itself is represented as the value of the content attribute of an X/HTML meta element, and a syntax encoding scheme URI is represented as a DC-HTML Prefixed Name which is the value of the scheme attribute of the X/HTML meta element.

The examples below show a description consisting of two statements with non-literal value surrogates. In the second statement the non-literal value surrogate contains a typed value string with the syntax encoding scheme URI http://www.w3.org/2001/XMLSchema#date:

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
   "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" >
<link rel="schema.XSD" href="http://www.w3.org/2001/XMLSchema#" >
<meta name="DCTERMS.title" lang="en" content="Services to Government" >
<meta name="DCTERMS.modified" scheme="XSD.date" content="2007-07-22" >
</head>
<body>
</body>
</html>

Example 17: Literal Value Surrogate with Typed Value String (HTML)

<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
     "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" />
<link rel="schema.XSD" href="http://www.w3.org/2001/XMLSchema#" />
<meta name="DCTERMS.title" xml:lang="en" content="Services to Government" />
<meta name="DCTERMS.modified" scheme="XSD.date" content="2007-07-22" />
</head>
<body>
</body>
</html>

Example 18: Literal Value Surrogate with Typed Value String (XHTML)

4.5.2 Encoding a Statement containing a Non-Literal Value Surrogate

In the DC-HTML profile, each statement containing a non-literal values surrogate is represented as an X/HTML link element.

4.5.2.1. The Property URI

A statement must contain exactly one property URI.

In the DC-HTML profile, a property URI in a statement containing a non-literal values surrogate is represented as a DC-HTML Prefixed Name which is the value of the rel attribute of an X/HTML link element.

The examples below shows a description consisting of a single statement where the property URI is http://purl.org/dc/terms/subject.

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
   "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" >
<link rel="DCTERMS.subject" href="http://example.org/topics/archives" title="Archives" >
</head>
<body>
</body>
</html>

Example 19: The Property URI as the value of the rel attribute (HTML)

<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
     "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" />
<link rel="DCTERMS.subject" href="http://example.org/topics/archives" title="Archives" />
</head>
<body>
</body>
</html>

Example 20: The Property URI as the value of the rel attribute (XHTML)

The HTML/XHTML rel attribute supports a list of linktypes, so where a description contains multiple statements referring to different properties but the same value, they may be represente using a single link element.

The examples below shows a description consisting of two statements where the property URIs are http://purl.org/dc/terms/creator and http://purl.org/dc/terms/publisher.

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
   "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" >
<link rel="DCTERMS.creator DCTERMS.publisher" href="http://example.org/agents/DCMI" title="Dublin Core Metadata Initiative" >
</head>
<body>
</body>
</html>

Example 21: Multiple Property URIs as the value of the rel attribute (HTML)

<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
     "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" />
<link rel="DCTERMS.creator DCTERMS.publisher" href="http://example.org/agents/DCMI" title="Dublin Core Metadata Initiative" />
</head>
<body>
</body>
</html>

Example 22: Multiple Property URIs as the value of the rel attribute (XHTML)

The same description could be represented using repeated link elements:

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
   "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" >
<link rel="DCTERMS.creator" href="http://example.org/agents/DCMI" title="Dublin Core Metadata Initiative" >
<link rel="DCTERMS.publisher" href="http://example.org/agents/DCMI" title="Dublin Core Metadata Initiative" >
</head>
<body>
</body>
</html>

Example 23: The Property URI as the value of the rel attribute (HTML)

<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
     "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" />
<link rel="DCTERMS.creator" href="http://example.org/agents/DCMI" title="Dublin Core Metadata Initiative" />
<link rel="DCTERMS.publisher" href="http://example.org/agents/DCMI" title="Dublin Core Metadata Initiative" />
</head>
<body>
</body>
</html>

Example 24: The Property URI as the value of the rel attribute (XHTML)

4.4.2.2 Encoding a Non-Literal Value Surrogate

In the subset of the DCAM description model supported by the DC-HTML profile, a non-literal value surrogate is made up of exactly one value URI and zero or one plain value strings.

In the DC-HTML profile, the value URI is represented as the value of the href attribute of the X/HTML link element

The examples below shows a description consisting of a single statement with a non-literal value surrogate made up of a value URI.

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
   "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" >
<link rel="DCTERMS.subject" href="http://example.org/topics/archives" >
</head>
<body>
</body>
</html>

Example 25: Non-Literal Value Surrogate with Value URI as value of href attribute (HTML)

<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
     "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" />
<link rel="DCTERMS.subject" href="http://example.org/topics/archives" />
</head>
<body>
</body>
</html>

Example 26: Non-Literal Value Surrogate with Value URI as value of href attribute (XHTML)

A plain value string may be associated with a value string language.

In the DC-HTML profile, the string itself is represented as the value of the title attribute of the X/HTML link element, and a value string language is represented by the value of the lang (HTML) or xml:lang (XHTML) attribute of the link element.

The examples below shows a description consisting of a single statement with a non-literal value surrogate made up of a value URI and a plain value string with no value string language.

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
   "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" >
<link rel="DCTERMS.subject" href="http://example.org/topics/archives" title="Archives" >
</head>
<body>
</body>
</html>

Example 27: Non-Literal Value Surrogate with Plain Value String as value of title attribute (HTML)

<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
     "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" />
<link rel="DCTERMS.subject" href="http://example.org/topics/archives" title="Archives" />
</head>
<body>
</body>
</html>

Example 28: Non-Literal Value Surrogate Plain Value String as value of title attribute (XHTML)

The examples below shows a description consisting of a single statement with a non-literal value surrogate made up of a value URI and a plain value string which includes a value string language.

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
   "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" >
<link rel="DCTERMS.subject" lang="en" href="http://example.org/topics/archives" title="Archives" >
</head>
<body>
</body>
</html>

Example 29: Non-Literal Value Surrogate with Plain Value String with Value String Language (HTML)

<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
     "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head profile="http://dublincore.org/documents/2007/07/27/dc-html/">
<title>Services to Government</title>
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" />
<link rel="DCTERMS.subject" xml:lang="en" href="http://example.org/topics/archives" title="Archives" />
</head>
<body>
</body>
</html>

Example 30: Non-Literal Value Surrogate Plain Value String with Value String Language (XHTML)

Appendix A. DC-TEXT Representation of Examples

This appendix provides representations of all the examples provided in the main body of the document using the DC-Text syntax [DC-TEXT].

A.1 Examples 1 & 2

The X/HTML instances in Examples 1 & 2 represent the following description set:

@prefix dcterms: <http://purl.org/dc/terms/> .
DescriptionSet (
  Description (
    Statement (
      PropertyURI ( dcterms:subject )
      ValueURI ( <http://example.org/topics/archives> )
    )
  )
)

A.2 Example 3 & 4

The X/HTML instances in Examples 3 & 4 represent the following description set:

@prefix dcterms: <http://purl.org/dc/terms/> .
DescriptionSet (
  Description (
    Statement (
      PropertyURI ( dcterms:isReferencedBy )
      ValueURI ( <http://example.org/docs/doc123> )
    )
  )
)

A.3 Example 5 & 6

The X/HTML instances in Examples 5 & 6 represent the following description set:

@prefix dcterms: <http://purl.org/dc/terms/> .
DescriptionSet (
  Description (
    Statement (
      PropertyURI ( dcterms:title )
      LiteralValueString ( "Services to Government" )
    )
  )
)

A.4 Example 7 & 8

The X/HTML instances in Examples 7 & 8 represent the following description set:

@prefix dcterms: <http://purl.org/dc/terms/> .
@prefix marcrel: <http://www.loc.gov/loc.terms/relators/> .
DescriptionSet (
  Description (
    Statement (
      PropertyURI ( dcterms:title )
      LiteralValueString ( "Services to Government" )
    )
    Statement (
      PropertyURI ( marcrel:EDT )
      ValueURI ( <http://example.org/agents/DeptOfObfuscation> )
    )
  )
)

A.5 Examples 9 & 10

The X/HTML instances in Examples 9 & 10 represent the following description set:

@prefix dcterms: <http://purl.org/dc/terms/> .
DescriptionSet (
  Description (
    Statement (
      PropertyURI ( dcterms:title )
      LiteralValueString ( "Services to Government" )
    )
    Statement (
      PropertyURI ( dcterms:subject )
      ValueURI ( <http://example.org/topics/archives> )
      ValueString ( "Archives" )
    )
  )
)

A.6 Examples 11 & 12

The X/HTML instances in Examples 11 & 12 represent the following description set:

@prefix dcterms: <http://purl.org/dc/terms/> .
DescriptionSet (
  Description (
    Statement (
      PropertyURI ( dcterms:title )
      LiteralValueString ( "Services to Government" )
    )
  )
)

A.7 Examples 13 & 14

The X/HTML instances in Examples 13 & 14 represent the following description set:

@prefix dcterms: <http://purl.org/dc/terms/> .
DescriptionSet (
  Description (
    Statement (
      PropertyURI ( dcterms:title )
      LiteralValueString ( "Services to Government" )
    )
  )
)

A.8 Examples 15 & 16

The X/HTML instances in Examples 15 & 16 represent the following description set:

@prefix dcterms: <http://purl.org/dc/terms/> .
DescriptionSet (
  Description (
    Statement (
      PropertyURI ( dcterms:title )
      LiteralValueString ( "Services to Government"
        Language ( en )
      )
    )
  )
)

A.9 Examples 17 & 18

The X/HTML instances in Examples 17 & 18 represent the following description set:

@prefix dcterms: <http://purl.org/dc/terms/> .
DescriptionSet (
  Description (
    Statement (
      PropertyURI ( dcterms:title )
      LiteralValueString ( "Services to Government"
        Language ( en )
      )
    )
    Statement (
      PropertyURI ( dcterms:modified )
      LiteralValueString ( "2007-07-22"
        SyntaxEncodingSchemeURI ( <http://www.w3.org/2001/XMLSchema#date> )
      )
    )
  )
)

A.10 Examples 19 & 20

The X/HTML instances in Examples 19 & 20 represent the following description set:

@prefix dcterms: <http://purl.org/dc/terms/> .
DescriptionSet (
  Description (
    Statement (
      PropertyURI ( dcterms:subject )
      ValueURI ( <http://example.org/topics/archives> )
      ValueString ( "Archives" )
    )
  )
)

A.11 Examples 21 & 22

The X/HTML instances in Examples 21 & 22 represent the following description set:

@prefix dcterms: <http://purl.org/dc/terms/> .
DescriptionSet (
  Description (
    Statement (
      PropertyURI ( dcterms:publisher )
      ValueURI ( <http://example.org/agents/DCMI> )
      ValueString ( "Dublin Core Metadata Initiative" )
    )
    Statement (
      PropertyURI ( dcterms:publisher )
      ValueURI ( <http://example.org/agents/DCMI> )
      ValueString ( "Dublin Core Metadata Initiative" )
    )
  )
)

A.12 Examples 23 & 24

The X/HTML instances in Examples 23 & 24 represent the following description set:

@prefix dcterms: <http://purl.org/dc/terms/> .
DescriptionSet (
  Description (
    Statement (
      PropertyURI ( dcterms:publisher )
      ValueURI ( <http://example.org/agents/DCMI> )
      ValueString ( "Dublin Core Metadata Initiative" )
    )
    Statement (
      PropertyURI ( dcterms:publisher )
      ValueURI ( <http://example.org/agents/DCMI> )
      ValueString ( "Dublin Core Metadata Initiative" )
    )
  )
)

A.13 Examples 25 & 26

The X/HTML instances in Examples 25 & 26 represent the following description set:

@prefix dcterms: <http://purl.org/dc/terms/> .
DescriptionSet (
  Description (
    Statement (
      PropertyURI ( dcterms:subject )
      ValueURI ( <http://example.org/topics/archives> )
    )
  )
)

A.14 Examples 27 & 28

The X/HTML instances in Examples 27 & 28 represent the following description set:

@prefix dcterms: <http://purl.org/dc/terms/> .
DescriptionSet (
  Description (
    Statement (
      PropertyURI ( dcterms:subject )
      ValueURI ( <http://example.org/topics/archives> )
      ValueString ( "Archives" )
    )
  )
)

A.15 Examples 29 & 30

The X/HTML instances in Examples 29 & 30 represent the following description set:

@prefix dcterms: <http://purl.org/dc/terms/> .
DescriptionSet (
  Description (
    Statement (
      PropertyURI ( dcterms:subject )
      ValueURI ( <http://example.org/topics/archives> )
      ValueString ( "Archives" 
        Language ( en )
      )
    )
  )
)

References

[DCAM]
DCMI Abstract Model DCMI Recommendation. 2007-06-04
http://dublincore.org/documents/2007/06/04/abstract-model/

[RFC3986]
Uniform Resource Identifier (URI): Generic Syntax.
http://www.ietf.org/rfc/rfc3986.txt

[GRDDL]
Gleaning Resource Descriptions from Dialects of Languages (GRDDL) W3C Candidate Recommendation 2 May 2007
http://www.w3.org/TR/2007/CR-grddl-20070502/

[DC-TEXT]
DC-Text: A Text Syntax for Dublin Core Metadata Draft of 2007-04-02.
http://dublincore.org/architecturewiki/DCText/2007-04-02

Changes in this version

Initial version, for 2007-06-04 version of DCAM

> DCXHTMLGuidelines/2007-07-27