Used for any kind of internal referencing
This element may be used to reference anything that has 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 Tag Sets.
Unlike the base Suite, the Book Tag Set’s and the Collection Tag Set’s content model for this element includes graphical elements for use in instances where, for example, an onscreen arrow serves as the link to a picture or database.
The @ref-type attribute (of the <xref> element) can be used to preserve information concerning what type of element is being pointed to by the cross-reference.
Display/Formatting Note: The content of the reference (if present) will be displayed as the link.
<!ELEMENT xref (#PCDATA %xref-elements;)* >
(#PCDATA | bold | italic | monospace | overline | overline-start | overline-end | roman | sans-serif | sc | strike | underline | underline-start | underline-end | alternatives | inline-graphic | private-char | graphic | media | named-content | styled-content | sub | sup)*
Any combination of:
<aff>, <alt-title>, <article-title>, <attrib>, <bold>, <book-title>, <chem-struct>, <collab>, <collection-name>, <comment>, <contrib>, <contrib-group>, <def-head>, <italic>, <kwd>, <license-p>, <meta-value>, <monospace>, <multi-link>, <named-content>, <overline>, <p>, <product>, <roman>, <sans-serif>, <sc>, <speaker>, <strike>, <styled-content>, <sub>, <subtitle>, <sup>, <td>, <term>, <term-head>, <th>, <title>, <trans-subtitle>, <trans-title>, <underline>
...
<sec id="bid.36">
<title>Microbial Genomes</title>
<p>... A CON entry, containing instructions on how to
put the pieces back together, is also made. The CON entry
contains descriptor information, such as source organism
and references, as well as a join statement providing
explicit instructions on how to generate the complete
genome from the pieces. The Accession number assigned to
the CON record is also added as a secondary Accession
number on each of the pieces that make up the complete
genome (see <xref ref-type="fig" rid="bid.37">Figure 2</xref>).
<fig id="bid.37">
<label>2</label>
<caption><title>A GenBank CON entry for a complete
bacterial genome.</title>
<p>The information toward the <italic>bottom</italic> of
the record describes how to generate the complete genome
from the pieces.</p>
</caption>
<graphic xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="ch1f2" mime-subtype="gif"/>
</fig>
</p>
...
</sec>
...
link3.ent