Abstract

Access to the World Wide Web has meant access to many types of content, including text, documents in a variety of formats such as the Open Document Format (ODF) or Portable Document Format (PDF), audio or video clips, and, of course, web content. Web content (e.g. XML, XHTML, and HTML documents), like many types of content, usually has a structure that allows identifying portions of the document in many ways.

This specification will contain a framework for representing pointers - entities that permit identifying a portion or segment of a piece of content - making use of the Resource Description Framework (RDF). It will also describe a number of specific types of pointers that permit portions of a document to be referred to in different ways. When referring to a specific part of, say, a piece of web content, it is useful to be able to have a consistent manner by which to refer to a particular segment of a web document, to have a variety of ways by which to refer to that same segment, and to make the reference robust in the face of changes to that document.

Status of this document

This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at http://www.w3.org/TR/.

The intent of the initial public draft of this specification is to introduce the Pointer Methods in RDF vocabulary, a collection of classes and properties that can be used to identify portions or segments of content, especially web content. Keep in mind that this specification is part of a larger suite of deliverables produced and maintained by the Evaluation and Repair Tools Working Group, but that it is meant to be consumable as an independent vocabulary. Feedback from the groups involved in the W3C Semantic Web Activity, especially the Semantic Web Coordination Group, the Semantic Web Deployment Working Group, the Semantic Web Interest Group, and the POWDER Working Group, would be greatly appreciated.

Besides the issues described in the editor's notes throughout this document, the group would apreciate feedback on:

Please send comments to the mailing list of the ERT WG. The archives for this list are publicly available.

This is an Editor's draft of the Pointers Vocabulary in RDF. Publication as a Working Draft does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.

This document was produced by a group operating under the 5 February 2004 W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.

This document has been produced by the Evaluation and Repair Tools Working Group as part of the WAI Technical Activity.

Table of Contents

  1. Introduction
  2. Classes
  3. Properties

Appendices

  1. Vocabulary Terms
  2. References
  3. Contributors

1. Introduction

This specification introduces an RDF vocabulary to enable certain parts within a document, particularly HTML and XML documents, to be pointed to in an accurate way. The document introduces a series of RDF classes and properties that can be used to point to parts of a document in different ways.

1.1. Namespaces

The namespace for Pointer Methods in RDF as specified in this draft is http://www.w3.org/2009/pointers# and uses the ptr prefix. Other namespaces typically used by Pointer Methods in RDF include the following:

cnt
The Representing Content in RDF namespace http://www.w3.org/2008/content# described in [Content]
rdf
The RDF namespace http://www.w3.org/1999/02/22-rdf-syntax-ns# described in [RDF]
rdfs
The RDF Schema namespace http://www.w3.org/2000/01/rdf-schema# described in [RDFS]

1.2. Document conventions

The keywords must, required, recommended, should, may, and optional are used in accordance with [RFC2119].

1.3. Use cases

One motivation for this vocabulary stems from methods for reporting test results such as the Evaluation and Report Language (EARL) [EARL] but this need not be its only application. Other typical applications could include:

This list is not meant to be exhaustive. This vocabulary is extensible, providing for alternative or enhanced methods for referring to portions of content and for referring to a variety of content types.

1.4. Pre-requisites

Pointer Methods in RDF is defined as an RDF vocabulary. The Resource Description Framework (RDF) is a general-purpose language for describing information in a way that is machine-understandable. The examples will be serialized with the abbreviated RDF/XML notation.

This document assumes the following background knowledge:

2. Classes

2.1 Pointer Class

Pointer - a method that could be used to point out different parts of electronic documents. It is an abstract class which is intended to be subclassed into more specific ones, and every other type of pointer must be a ptr:Pointer subclass.

This abstract class can not be used directly, one of the more specific refinements contained in this document must be used instead.

Related Properties

Properties defined by this document:

in domain of:
in range of:
none

2.2 PointersGroup Class

Pointers Group - a generic container for a group of pointers without any specific relationship between them.

Related Properties

Properties defined by this document:

in domain of:
none
in range of:

Related Classes

While the generic PointersGroup class can be used directly, one of the following more specific refinements should be used instead to provide more information about the existing relationship between the group members:

ptr:RelatedPointers
A group of related pointers you use together for some purpose.
ptr:EquivalentPointers
A group of pointers that point simoultaneously to the same part of the document.

Examples:

Example 1: A series of pointers grouped using a PointersGroup resource.

<ptr:PointersGroup rdf:about="#group">
  <ptr:groupPointer rdf:resource="#pointer1"/>
  <ptr:groupPointer rdf:resource="#pointer2"/>
  ...
</ptr:PointersGroup>

2.2.1 RelatedPointers Class

Related Pointers - a group of pointers to be grouped together for some purpose, indicating that the group members (presumably pointing to different parts of the document) have some relationship because they have a meaning as a whole. This is a subclass of the PointersGroup class

Related Properties

Properties defined by this document:

in domain of:
none
in range of:
none

Examples:

Example 2: A group of related pointers.

<ptr:RelatedPointers rdf:about="#relatedGroup">
  <ptr:groupPointer rdf:resource="#relatedPointer1"/>
  <ptr:groupPointer rdf:resource="#relatedPointer2"/>
  ...
</ptr:RelatedPointers>

2.2.2 EquivalentPointers Class

Equivalent Pointers - a group of pointers that point simoultaneously to the same part of the document, so that they can be considered equivalent. Put another way, each pointer in a set of pointers that are identified as equivalent must identify or pick out the same piece of content. This is a subclass of the PointersGroup class

In order to achieve the maximum level of flexibility and interoperability, it is recommended to provide as much equivalent pointers as possible for any case.

Related Properties

Properties defined by this document:

in domain of:
none
in range of:
none

Examples:

Example 3: A series of equivalent pointers.

<ptr:EquivalentPointers rdf:about="#equivalentGroup">
  <ptr:groupPointer rdf:resource="#equivalentPointer1"/>
  <ptr:groupPointer rdf:resource="#equivalentPointer2"/>
  <ptr:groupPointer rdf:resource="#equivalentPointer3"/>
  ...
</ptr:EquivalentPointers>

2.3 SinglePointer Class

Single Pointer - a pointing method made up of a unique pointer. This is an abstract single pointer that provides the necessary framework, but it does not provide any kind of pointer, so more specific subclasses must be used.

Related Properties

Properties defined by this document:

in domain of:
in range of:

Related Classes

This vocabulary already provides several subclasses that refine the SinglePointer class in relation to the way the pointer is defined.

ptr:ExpressionPointer
A single pointer that makes use of expression languages to point out parts of a document.
ptr:OffsetPointer
A single pointer that points out parts of a document by means of an offset number counting from the start of the reference.
ptr:LineCharPointer
A single pointer that points out a part of a document by means of the line number and character position where it is located.

Examples:

Example 4: A SinglePointer resource.

<ptr:SinglePointer rdf:about="#singlePointer">
  <ptr:reference rdf:resource="http://example.org/doc1.html"/>
</ptr:SinglePointer>

2.3.1 ExpressionPointer Class

Expression Pointer - a single pointer that makes use of expression languages to point out parts of a document. This is a generic expression pointer that could be subclassed for extensibility, more specific subclasses should be used where suitable.

Related Properties

Properties defined by this document:

in domain of:
in range of:
none

Related Classes

This vocabulary already provides several subclasses of the ExpressionPointer class depending on the language that is used to define the pointer expression.

ptr:XPathPointer
An expression pointer that makes use of XPath expressions to point out parts of a document.
ptr:CSSSelectorPointer
An expression pointer that points out different parts of a document by means of CSS selectors.

Examples:

Example 5: an ExpressionPointer resource with version information.

<ptr:ExpressionPointer rdf:about="#expressionPointer">  
  <ptr:expression>some expression</ptr:expression>
  <ptr:version>x.y</ptr:version>
  <ptr:reference rdf:resource="http://example.org/doc1.html"/> 
</ptr:ExpressionPointer>
2.3.1.1 XPathPointer Class

XPath Pointer - An expression pointer that makes use of XPath [XPath] expressions to point out parts of a document.

Related Properties

Properties defined by this document:

in domain of:
in range of:
none

Related Classes

ptr:XMLNamespace
An XML Namespace.
ptr:XPointerPointer
An expression pointer that makes use of the XPointer Framework expressions to point out parts of a document.

Examples:

Example 6: An XPathPointer resource with namespace reference.

<ptr:XPathPointer rdf:about="#xPathPointer">
  <ptr:version>2.0</ptr:version>
  <ptr:expression>/html/body/div[@id='header']/img[1]</ptr:expression>
  <ptr:reference rdf:resource="http://example.org/doc1.html"/>
  <ptr:namespace rdf:resource="#xmlNamespace1"/>
</ptr:XPathPointer>
2.3.1.1.1 XMLNamespace Class

XML Namespace - a namespace as defined by [Namespaces].

Related Properties

Properties defined by this document:

in domain of:
in range of:

Examples:

Example 7: An XMLNamespace resource indicating prefix and name.

<ptr:XMLNamespace rdf:about="#XMLnamespace1">
  <ptr:prefix>eg</ptr:prefix>
  <ptr:namespaceName>http://example.org/ns/</ptr:namespaceName>
</ptr:XMLNamespace>
2.3.1.1.2 XPointerPointer Class

XPointer Pointer - an expression pointer that makes use of xpointer() scheme [XPointer-SCH] expressions to point out parts of a document.

Related Properties

Properties defined by this document:

in domain of:
none
in range of:
none

Examples:

Example 8: A XPointerPointer resource.

<ptr:XPointerPointer rdf:about="#xPointerPointer">
  <ptr:expression>string-range(//P,"Thomas Pynchon")[3],"P",1,0)</ptr:expression>
  <ptr:reference rdf:resource="http://example.org/doc1.html"/>  
</ptr:XPointerPointer>
2.3.1.2 CSSSelectorPointer Class

CSS Selector Pointer - an expression pointer that points out parts of a document by means of a CSS expression.

Related Properties

Properties defined by this document:

in domain of:
none
in range of:
none

Examples:

Example 9: A CSSSelector resource with version information.

<ptr:CSSSelectorPointer rdf:about="#cssSelectorPointer">
  <ptr:reference rdf:resource="http://example.org/doc1.html"/>  
  <ptr:expression>body > p#important</ptr:expression> 
  <ptr:version>2.1</ptr:version> 
</ptr:CSSSelectorPointer>

2.3.2 OffsetPointer Class

Offset Pointer - a single pointer that points out parts of a document by means of an offset number counting from the start of the reference.

Related Properties

Properties defined by this document:

in domain of:
in range of:
none

Related Classes

While the generic OffsetPointer class can be used directly, one of the following more specific refinements should be used instead to provide more information about the type of offset that is being used.

ptr:CharOffsetPointer
A single pointer that points out parts of a document by means of a character offset from the start of the reference.
ptr:ByteOffsetPointer
A single pointer that points out parts of a document by means of a byte offset from the start of the reference.

Examples:

Example 2.10: An OffsetPointer resource.

<ptr:OffsetPointer rdf:about="#offsetPointer">
  <ptr:reference rdf:resource="http://example.org/doc1.html"/>  
  <ptr:offset>33</ptr:offset> 
</ptr:OffsetPointer>
2.3.2.1 CharOffsetPointer Class

Char Offset Pointer - a single pointer that points out parts of a document by means of a character offset from the start of the reference.

Related Properties

Properties defined by this document:

in domain of:
none
in range of:
none

Examples:

Example 2.11: A CharOffsetPointer resource.

<ptr:CharOffsetPointer rdf:about="#charOffsetPointer">
  <ptr:reference rdf:resource="http://example.org/doc1.html"/>  
  <ptr:offset>335</ptr:offset> 
</ptr:CharOffsetPointer>
2.3.2.2 ByteOffsetPointer Class

Byte Offset Pointer - a single pointer that points out parts of a document by means of a byte offset from the start of the reference.

Related Properties

Properties defined by this document:

in domain of:
none
in range of:
none

Examples:

Example 2.12: A ByteOffsetPointer resource.

<ptr:ByteOffsetPointer rdf:about="#byteOffsetPointer">
  <ptr:reference rdf:resource="http://example.org/doc1.html"/>  
  <ptr:offset>52</ptr:offset> 
</ptr:ByteOffsetPointer>

2.3.3 LineCharPointer Class

Line Char Pointer - a single pointer that points out parts of a document by means of the line number and character position where the target is localized.

Related Properties

Properties defined by this document:

in domain of:
in range of:
none

Examples:

Example 2.13: A LineCharPointer resource.

<ptr:LineCharPointer rdf:about="#lineCharPointer">
  <ptr:reference rdf:resource="http://example.org/doc1.html"/>  
  <ptr:lineNumber>5</ptr:lineNumber>
  <ptr:charNumber>18</ptr:charNumber>
</ptr:LineCharPointer>

2.4 CompoundPointer Class

Compound Pointer - a pointing method made up of a pair of pointers that identify a well defined section within a document delimited by a begin and an end.

This is an abstract compound pointer that provides the necessary framework, but it does not constitute a complete compound pointer, as it only defines the start point of the section. One of the more specific subclasses must be used instead.

Related Properties

Properties defined by this document:

in domain of:
in range of:
none

Related Classes

ptr:StartEndPointer
A compound pointer that points out parts of a document by means of a range delimited by a start point and an end point.
ptr:CharSnippetCompoundPointer
A compound pointer that points out parts of a document by means of a range delimited by a starting point and a character snippet from that starting point.
ptr:CharOffsetCompoundPointer
A compound pointer that points out parts of a document by means of a range delimited by a starting point and a character offset from that starting point.
ptr:ByteSnippetCompoundPointer
A compound pointer that points out parts of a document by means of a range delimited by a starting point and a byte snippet from that starting point.
ptr:ByteOffsetCompoundPointer
A compound pointer that points out parts of a document by means of a range delimited by a starting point and a byte offset from that starting point.

2.4.1 StartEndPointer Class

Start End Pointer - a compound pointer pointing out parts of a document by means of a range delimited by a pair of single pointers that define the start point and the end point.

Related Properties

Properties defined by this document:

in domain of:
in range of:
none

Examples:

Example 2.14: A StartEndPointer resource.

<ptr:StartEndPointer rdf:about="#startEndPointer">
  <ptr:startPointer rdf:resource="#lineCharPointer"/>   
  <ptr:endPointer rdf:resource="#charOffsetPointer"/>   
</ptr:StartEndPointer>

2.4.2 CharSnippetCompoundPointer Class

Char Snippet Compound Pointer - a compound pointer pointing out parts of a document by means of a range delimited by a single pointer that defines the start point and a character snippet from there.

Related Properties

Properties defined by this document:

in domain of:
none
in range of:
none

Properties not defined by this document:

cnt:chars external link
Character string representing the character sequence of the given content.

Examples:

Example 2.15: A CharSnippetCompoundPointer resource.

<ptr:CharSnippetCompoundPointer rdf:about="#charSnippetCompoundPointer">
  <ptr:startPointer rdf:resource="#charOffsetPointer"/>   
  <cnt:chars>&lt;p&gt;Some text.&lt;/p&gt;</cnt:chars>   
</ptr:CharSnippetCompoundPointer>

2.4.3 CharOffsetCompoundPointer Class

Char Offset Compound Pointer - a compound pointer pointing out parts of a document by means of a range delimited by a single pointer that defines the start point and a character offset from there.

Related Properties

Properties defined by this document:

in domain of:
in range of:
none

Examples:

Example 2.16: A CharOffsetCompoundPointer resource.

<ptr:CharOffsetCompoundPointer rdf:about="#charOffsetCompoundPointer">
  <ptr:startPointer rdf:resource="#XPathPointer"/>   
  <ptr:charOffset>55</ptr:charOffset>   
</ptr:CharOffsetCompoundPointer>

2.4.4 ByteSnippetCompoundPointer Class

Byte Snippet Compound Pointer - a compound pointer pointing out parts of a document by means of a range delimited by a single pointer that defines the start point and a byte snippet from there.

Related Properties

Properties defined by this document:

in domain of:
none
in range of:
none

Properties not defined by this document:

cnt:bytes external link
Character string representing the Base64 encoded byte sequence of the given content.

Examples:

Example 2.17: A ByteSnippetCompoundPointer resource.

<ptr:ByteSnippetCompoundPointer rdf:about="#byteSnippetCompoundPointer">
  <ptr:startPointer rdf:resource="#byteOffsetPointer"/>   
  <cnt:bytes>R0lGODlhtQAxAOYAAKynpv3t4v3j1P/59ZuXlveYZ/vDovvMsfBbGWRiYf7+{...}</cnt:bytes>   
</ptr:ByteSnippetCompoundPointer>

2.4.5 ByteOffsetCompoundPointer Class

Byte Offset Compound Pointer - a compound pointer pointing out parts of a document by means of a range delimited by a single pointer that defines the start point and a byte offset from there.

Related Properties

Properties defined by this document:

in domain of:
in range of:
none

Examples:

Example 2.18: A ByteOffsetCompoundPointer resource.

<ptr:ByteOffsetCompoundPointer rdf:about="#byteOffsetCompoundPointer"> 
  <ptr:startPointer rdf:resource="#byteOffsetPointer"/>   
  <ptr:byteOffset>255</ptr:byteOffset>   
</ptr:ByteOffsetCompoundPointer>

3. Properties

3.1 groupPointer Property

A reference to a specific pointer.

A PointersGroup will have one groupPointer property per each of the pointers it contains. As any group of pointers must have one or more pointers, instances of the PointersGroup class must have at least one instance of the groupPointer property.

Domain:
ptr:PointersGroup
Range:
ptr:Pointer

3.2 reference Property

The document within which the pointer is applicable or meaningful.

A SinglePointer must have exactly one reference.

Domain:
ptr:SinglePointer
Range:
none

3.3 expression Property

The language expression used as pointer.

An ExpressionPointer must have exactly one expression.

Domain:
ptr:ExpressionPointer
Range:
Literal

3.4 version Property

The language version used in the pointer expression.

An ExpressionPointer must have at most one version.

Domain:
ptr:ExpressionPointer
Range:
Literal

3.5 namespace Property

The namespace within an XPath expression operates.

Domain:
ptr:XPathPointer
Range:
ptr:XMLNamespace

3.6 prefix Property

Associates element and attribute names with a namespace URI.

An XMLNamespace must have exactly one prefix

Domain:
ptr:XMLNamespace
Range:
none

3.7 namespaceName Property

Identifies the namespace.

An XMLNamespace must have exactly one namespace

Domain:
ptr:XMLNamespace
Range:
none

3.8 offset Property

The target position counting from the start of the referenced document. The count will start at one in each document.

An OffsetPointer must have exactly one offset

Domain:
ptr:OffsetPointer
Range:
Positive Integer

3.9 lineNumber Property

The line number where the target is localized. The line count will start at one in each document.

A LineCharPointer must have exactly one lineNumber.

Domain:
ptr:LineCharPointer
Range:
Positive Integer

3.10 charNumber Property

The character number where the target is localized within a line. The character count will start at one in each line.

A LineCharPointer must have at most one charNumber.

Domain:
ptr:LineCharPointer
Range:
Positive Integer

3.12 startPointer Property

Reference to the pointer that defines the beginning point for a range.

A CompoundPointer must have exactly one startPointer.

Domain:
ptr:CompoundPointer
Range:
ptr:SinglePointer

3.13 endPointer Property

Reference to the pointer that defines the end point for a range.

A StartEndPointer must have exactly one endPointer.

Domain:
ptr:StartEndPointer
Range:
ptr:SinglePointer

3.14 charOffset Property

The position of the end of a range from a startPointer, expressed by the number of characters that conform the range, and being the first character of the range that one indicated by the startPointer.

A CharOffsetCompoundPointer must have exactly one charOffset.

Domain:
ptr:CharOffsetCompoundPointer
Range:
Positive Integer

3.15 byteOffset Property

The position of the end of a range from a startPointer, expressed by the number of bytes that conform the range, and being the first byte of the range that one indicated by the startPointer.

A ByteOffsetCompoundPointer must have exactly one byteOffset.

Domain:
ptr:ByteOffsetCompoundPointer
Range:
Positive Integer

Appendix A: Vocabulary Terms

The following terms are defined by this specification:

Classes

Classes in the Pointer Methods namespace
Class name Label Suggested types Required properties Optional properties
ptr:ByteOffsetPointer Byte Offset Pointer ptr:offset, ptr:reference
ptr:ByteOffsetCompoundPointer Byte Offset Compound Pointer ptr:byteOffset, ptr:startPointer
ptr:ByteSnippetCompoundPointer Byte Snippet Compound Pointer cnt:bytes external link, ptr:startPointer
ptr:CharOffsetPointer Char Offset Pointer ptr:offset, ptr:reference
ptr:CharOffsetCompoundPointer Char Offset Compound Pointer ptr:charOffset, ptr:startPointer
ptr:CharSnippetCompoundPointer Char Snippet Compound Pointer cnt:chars external link, ptr:startPointer
ptr:CSSSelectorPointer CSS selector Pointer ptr:expression, ptr:reference ptr:version
ptr:EquivalentPointers Equivalent Pointers ptr:groupPointer
ptr:ExpressionPointer Expression Pointer ptr:CSSSelectorPointer, ptr:XPathPointer, ptr:XPointerPointer ptr:expression, ptr:reference ptr:version
ptr:LineCharPointer Line-Char Pointer ptr:lineNumber, ptr:reference ptr:charNumber
ptr:XMLNamespace XMLNamespace ptr:namespaceURI, ptr:prefix
ptr:OffsetPointer Offset Pointer ptr:ByteOffsetPointer, ptr:CharOffsetPointer ptr:offset
ptr:Pointer Pointer ptr:PointersGroup, ptr:CompoundPointer, ptr:SinglePointer
ptr:PointersGroup Pointers Group ptr:EquivalentPointers, ptr:RelatedPointers ptr:groupPointer
ptr:CompoundPointer Compound Pointer ptr:StartEndPointer, ptr:CharSnippetCompoundPointer, ptr:CharOffsetCompoundPointer, ptr:ByteSnippetCompoundPointer, ptr:ByteOffsetCompoundPointer ptr:startPointer
ptr:RelatedPointers Related Pointers ptr:groupPointer
ptr:SinglePointer Single Pointer ptr:OffsetPointer, ptr:ExpressionPointer, ptr:LineCharPointer, ptr:reference
ptr:StartEndPointer Start-End Pointer ptr:endPointer, ptr:startPointer
ptr:XPathPointer XPath Pointer ptr:expression, ptr:reference ptr:namespace, ptr:version
ptr:XPointerPointer XPointer Pointer ptr:expression, ptr:reference ptr:namespace, ptr:version

Properties

Properties in the Pointers namespace
Property name Label Domain Range Restriction
ptr:byteOffset char offset ptr:ByteOffsetCompoundPointer Positive Integer Exactly one per ptr:ByteOffsetCompoundPointer
ptr:charNumber char number ptr:LineCharPointer Positive Integer At most one per ptr:LineCharPointer
ptr:charOffset char offset ptr:CharOffsetCompoundPointer Positive Integer Exactly one per ptr:CharOffsetCompoundPointer
ptr:endPointer end pointer ptr:StartEndPointer ptr:SinglePointer Exactly one per ptr:StartEndPointer
ptr:expression expression ptr:ExpressionPointer Literal Exactly one per ptr:ExpressionPointer
ptr:lineNumber line number ptr:LineCharPointer Positive Integer Exactly one per ptr:LineCharPointer
ptr:namespace namespace ptr:XPathPointer ptr:XMLNamespace
ptr:namespaceURI namespace URI ptr:XMLNamespace Exactly one per ptr:XMLNamespace
ptr:offset offset ptr:OffsetPointer Positive Integer Exactly one per ptr:OffsetPointer and ptr:StartOffsetPointer
ptr:groupPointer group pointer ptr:PointersGroup ptr:Pointer At least one per ptr:PointerGroup
ptr:prefix prefix ptr:XMLNamespace Literal Exactly one per ptr:XMLNamespace
ptr:reference reference ptr:SinglePointer Exactly one per ptr:SinglePointer
ptr:startPointer start pointer ptr:CompoundPointer ptr:SinglePointer Exactly one per ptr:CompoundPointer
ptr:version version ptr:ExpressionPointer Literal At most one per ptr:ExpressionPointer

Appendix B: References

[Content]
Representing Content in RDF - W3C Working Draft, 27 March 2008. J. Koch, C.A. Velasco eds.
http://www.w3.org/WAI/ER/Content/WD-Content-in-RDF-20080327
[EARL]
Evaluation and Report Language (EARL) 1.0 Schema - W3C Working Draft, 23 March 2007. S. Abou-Zahra ed.
http://www.w3.org/TR/2007/WD-EARL10-Schema-20070323/
[Namespaces]
Namespaces in XML 1.1 (Second Edition) - W3C Recommendation, 16 August 2006. T. Bray, D. Hollander, A. Layman, R. Tobin eds.
http://www.w3.org/TR/2006/REC-xml-names11-20060816
[RDF]
RDF/XML Syntax Specification (Revised) - W3C Recommendation, 10 February 2004. D. Beckett ed.
http://www.w3.org/TR/2004/REC-rdf-syntax-grammar-20040210/
[RDF-PRIMER]
RDF Primer - W3C Recommendation, 10 February 2004. F. Manola, E.Miller eds.
http://www.w3.org/TR/rdf-primer/
[RDFS]
RDF Vocabulary Description Language 1.0: RDF Schema - W3C Recommendation, 10 February 2004. D. Brickley, R.V. Guha eds.
http://www.w3.org/TR/rdf-schema/
[RDF-XML-DIFFS]
Why RDF model is different from the XML model - Paper, September 1998. T. Berners-Lee.
http://www.w3.org/DesignIssues/RDF-XML
[RFC2119]
Key words for use in RFCs to Indicate Requirement Levels - IETF RFC, March 1997.
http://www.ietf.org/rfc/rfc2119.txt
[XML]
Extensible Markup Language (XML) 1.0 (Fourth Edition). W3C Recommendation 16 August 2006, edited in place 29 September 2006. T. Bray, J. Paoli, C.M. Sperberg-McQueen, E. Maler, F. Yergeau eds.
http://www.w3.org/TR/xml/
[XPath]
XML Path Language (XPath) 1.0. W3C Recommendation 16 November 1999. J. Clark, S. DeRose eds.
http://www.w3.org/TR/1999/REC-xpath-19991116
[XPointer-SCH]
XPointer xpointer() scheme. W3C Working Draft 19 December 2002. S. DeRose, E. Maler, R. Daniel eds.
http://www.w3.org/TR/2002/WD-xptr-xpointer-20021219/

Appendix C: Contributors

EARL is the result of the work of many people, the editor apologises for any names left out of this list, and will endeavour to rectify any errors noted in comments.

Contributors to this and/or previous Working Drafts

Shadi Abou-Zahra, Chrisoula Alexandraki, Sandor Herramhof, Carlos Iglesias, Nick Kew, Johannes Koch, Jim Ley, Charles McCathieNevile, Yehya Mohamed, Chris Ridpath, Christophe Strobbe, Michael Squillace and Carlos Velasco.