Number of a journal (or other document) within its series.
The <volume> element is used in two contexts: as a part of the metadata describing the article itself, and as part of a description of a cited work inside a bibliographic reference (<citation> or <nlm-citation>). For extensive examples of formatted <nlm-citation>s including use of <volume>s in <nlm-citation>s, see: Sample PubMed Central Citations. To see tagged versions of these examples, see: Sample PubMed Central Citations - XML Tagged.
Text, numbers, or special characters.
In article metadata
...
<article-meta>
<article-id pub-id-type="pmid">10092260</article-id>
<title-group>
<article-title>Systematic review of day hospital care
for elderly people</article-title>
</title-group>
<contrib-group>...</contrib-group>
<aff>...</aff>
<author-notes>...</author-notes>
<pub-date pub-type="pub"><day>27</day>
<month>3</month><year>1999</year></pub-date>
<volume>318</volume>
<issue>7187</issue>
<fpage>837</fpage>
<lpage>841</lpage>
<history><date date-type="accepted">
<day>29</day><month>1</month>
<year>1999</year></date>
</history>
<copyright-statement>...</copyright-statement>
<copyright-year>...</copyright-year>
<abstract>...</abstract>
</article-meta>
...
In a NLM-style bibliographic citation
<nlm-citation citation-type="journal">
<person-group>
<name>
<surname>You</surname>
<given-names>CH</given-names>
</name>
<name>
<surname>Lee</surname>
<given-names>KY</given-names>
</name>
<name>
<surname>Chey</surname>
<given-names>RY</given-names>
</name>
<name>
<surname>Menguy</surname>
<given-names>R</given-names>
</name>
</person-group>
<article-title>Electrogastrographic study of patients with unexplained nausea,
bloating and vomiting</article-title>
<source>Gastroenterology</source>
<year>1980</year>
<month>08</month>
<volume>79</volume>
<issue>2</issue>
<fpage>311</fpage>
<lpage>314</lpage>
</nlm-citation>
common.ent