Used for any kind of internal article referencing
This element may be used to reference anything that has an id attribute (an attribute of type id). 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 journal DTDs.
Display/Formatting Note: The content of the reference (if present) will be displayed as the link.
<!ELEMENT xref (#PCDATA %xref-elements;)* >
Any combination of:
<aff> Affiliation; <alt-title> Alternate Title; <article-title> Article Title; <attrib> Attribution; <bold> Bold; <chem-struct> Chemical Structure (Display); <collab> Collaborative (Group) Author; <comment> Comment in a Citation; <contrib> Contributor; <contrib-group> Contributor Group; <def-head> Definition List: Definition Head; <italic> Italic; <meta-name> Metadata Data Name for Custom Metadata; <meta-value> Metadata Data Name For Custom Metadata; <monospace> Monospace Text (Typewriter Text); <named-content> Named Special (Subject) Content; <overline> Overline; <p> Paragraph; <product> Product Information; <sc> Small Caps; <speaker> Speaker; <strike> Strike Through; <sub> Subscript; <subtitle> Article Subtitle; <sup> Superscript; <td> Table Data Cell (XHTML table model); <term> Definition List: Term; <term-head> Definition List: Term Head; <th> Table Header Cell (XHTML table model); <title> Title; <trans-title> Translated Title; <underline> Underline
<article> <front> ... </front> <body>... <p>Geriatric day hospitals developed rapidly in the United Kingdom in the 1960s as an important component of care provision. ... Although there is considerable descriptive literature on day hospital care,<xref ref-type="bibr" rid="B1">1</xref> concern has been expressed that evidence for effectiveness is equivocal and that day hospital care is expensive.<xref ref-type="bibr" rid="B2">2</xref> ...</p> ... </body> <back>... <ref-list> <ref id="B1"> <nlm-citation><collab>Research Unit of the Royal College of Physicians and British Geriatric Society</collab><source>Geriatric day hospitals: their role and guidelines for good practice</source><year>1994</year><publisher-loc>London</publisher-loc><publisher-name>RCP</publisher-name></nlm-citation></ref> <ref id="B2"> <nlm-citation><collab>National Audit Office</collab><source>National health service day hospitals for elderly people in England</source> <year>1994</year><publisher-loc>London</publisher-loc><publisher-name>HMSO</publisher-name></nlm-citation></ref> ... </ref-list> </back> </article>