ref-type Type of Cross-Reference

Type of element that is the target of the cross-reference (for example, a figure (“fig”), a table (“table”), or a footnote (“fn”). The values may be used for type-specific processing or validation.


The <xref> element may be used to reference any element in the standard document that has an @id attribute. This single element takes the place of the many named types of references (such as figure references, table references, and footnote references) that are common in many tag sets. This attribute states the element to which the cross-reference is pointing.
OPTIONAL on element: <xref>
Value Meaning
abbreviation Abbreviation or acronym.
aff Affiliation.
app Appendix.
author-notes Author notes.
award Points to the description of or identifier for a grant or award (<award-id>).
bibr Bibliographic reference (typically to a <ref> element, but it may point to a <element-citation> or an <mixed-citation> if there are multiple citations inside the <ref> element).
bio Biography
boxed-text Textbox or sidebar.
chem Chemical structure (to a <chem-struct> or <chem-struct-wrap> element).
contrib Contributor.
collab Collaboration.
corresp Corresponding author.
custom Not one of the meanings named in this list. The type can be found as the value of the attribute @custom-type.
disp-formula Display formula.
fig Figure or group of figures (to a <fig> or <fig-group> element).
fn Footnote.
kwd Keyword.
list List or list item (to a <list> or <list-item> element; also, possibly to a <def-list> or <def-item> element).
other None of the items listed.
plate Plate.
scheme Scheme.
sec Section.
statement Statement.
supplementary-material Supplementary information.
table Table or group of tables (to a <table-wrap> or <table-wrap-group> element).
table-fn Table footnote.
Restriction This is an optional attribute; there is no default.
Tagged Samples
Cross-reference to figure
<sec id="s5_1">
 <title>Two approaches to addressing accessibility in 
 <p><xref ref-type="fig" rid="f1">Figure 1</xref> provides 
  a graphical summary of how this Guide can be used.</p>
 <fig id="f1" orientation="portrait" position="anchor">
  <label>Figure 1</label>
   <title>Two approaches to address accessibility in 
  <graphic xlink:href="g3658.jpg"/>
Cross-reference to bibliographic citation
  <app content-type="inform-annex" id="annA">
   <label>Annex A</label>
   <title>Global trends supporting accessibility</title>
   <sec id="A1">
    <title>Trends in global demographics and market diversity</title>
    <p>According to the <italic>World Report on Disability</italic> 
     (published by the World Health Organization and the World Bank 
     in June 2011,<sup><xref ref-type="bibr" rid="bibr40">[40]</xref></sup> 
     approximately 15 % of the world population (over one billion 
     people) has ...</p>
  <ref id="bibr40">
    ><person-group><collab>World Health Organization</collab>, 
     <collab>World Bank</collab></person-group>. 
    <year iso-8601-date="2011">2011</year>), 
    <source>World Report on Disability</source>, 
    <publisher-loc>Geneva</publisher-loc>, available at: