Container element for categorization information about one of the large-scale components that comprise the body of a book, such as a chapter, unit, or module (all called <book-part>)
<!ELEMENT book-part-categories %book-part-categories-model; >
(subj-group+)
<subj-group> Subject Group, one or more
<book>
<book-meta>...</book-meta>
<book-front>...</book-front>
<body>
<book-part id="bid.2" book-part-type="chapter" book-part-number="1">
<book-part-meta>
<book-part-categories>
<subj-group>
<subject>Physical Sciences</subject>
<subj-group>
<subject>Chemistry</subject>
</subj-group>
</subj-group>
<subj-group>
<subject>Biological Sciences</subject>
<subj-group>
<subject>Biophysics</subject>
</subj-group>
</subj-group>
</book-part-categories>
<title-group>
<title>GenBank: The Nucleotide Sequence Database</title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name><surname>Mizrachi</surname>
<given-names>Ilene</given-names></name>
</contrib>
</contrib-group>
<history>...</history>
</book-part-meta>
<body>
<sec id="bid.3">...</sec>
</body>
<back>...</back>
</book-part>
</body>
</book>
bookpart3.ent