Container element for any series information used in a bibliographic reference (<citation>)
Within a citation to a non-journal item (for example, a book possibly spanning multiple volumes), the <series> element can contain the unique title of the entire series, as shown in the tagged example below. Similarly, some issues of journals are part of publishing series; within a bibliographic reference, this series information can be tagged using the <series> element.
<!ELEMENT series (#PCDATA %series-elements;)* >
Any combination of:
<book-meta> Book Metadata; <citation> Citation; <related-article> Related Article Information; <related-object> Related Object Information
...
<ref id="B1"><label>1</label>
<citation citation-type="book">
<name><surname>...</surname></name> and
<name><surname>...</surname></name>.
<year>1989</year>. <series>The Birds of
South America</series>. <volume>1</volume>.
<source>The Oscine Passerines</source>.
<publisher-name>University of Texas
Press</publisher-name>,
<publisher-loc>Austin</publisher-loc>
</citation>
</ref>
...
references.ent