Typically, the year of publication for a book or other work, but also the year “historical” events in a publishing cycle occurred, for example, the year a manuscript was last updated.
The <year> element is used in two contexts: as a part of the metadata concerning book or book component (such as a chapter), and as part of a description of a cited work inside a bibliographic reference (<citation> or <nlm-citation>) element.
Conversion Note: When possible, the year should be expressed as a 4-digit number, for example, “1776”, “1924”, or “0042”.
<!ELEMENT year (#PCDATA) >
Text, numbers, or special characters
<citation> Citation; <date> Date; <nlm-citation> NLM Citation Model; <pub-date> Publication Date; <related-article> Related Article Information; <related-object> Related Object Information; <string-date> Date as a String
In a bibliographic reference (punctuation and spacing removed):
...<ref-list>
<title>References</title>
<ref id="bid.41">
<label>1</label>
<citation>
<person-group>
<name><surname>Olson</surname><given-names>M</given-names></name>
...
</person-group>
<article-title>A common language for physical mapping
of the human genome</article-title>
<source>Science</source>
<year>1989</year>
<volume>245</volume>
<issue>4925</issue>
<fpage>1434</fpage>
<lpage>1435</lpage>
<pub-id pub-id-type="pmid">2781285</pub-id>
</citation>
</ref>
</ref-list>...
In a bibliographic reference (punctuation and spacing preserved):
...<ref-list>
<title>References</title>
<ref id="B8"><label>8</label>
<citation>
<name><surname>Weissert</surname>
<given-names>W</given-names></name>,
<name><surname>Livieratos</surname>
<given-names>B</given-names>
</name>. <article-title>Effects and costs of
day-care services for the chronically ill: a randomized
experiment</article-title>. <source>Medical Care</source>
<year>1980</year>; <volume>18</volume>:
<fpage>567</fpage>–<lpage>584</lpage>.
<pub-id pub-id-type="publisher-id">WES-6772889</pub-id>.
</citation>
</ref>
</ref-list>...
common.ent