A major organizational unit of a book, typically called a “chapter”, but given many names in common language, for example, chapter, part, unit, module, section, topic, lesson, canto, volume, or even “book”.
Book Parts are recursive, that is, various levels of <book-part> are indicated by containment, not by different names for the interior parts. The body of a book part (<body>) may contain lower level <book-part> elements or just recursive sections that are tagged using the <sec> element.
<!ELEMENT book-part %book-part-model; >
(book-part-meta?, front-matter?, body?, back?)
The following, in order:
<book dtd-version="1.0">
<book-meta>...</book-meta>
<front-matter>...</front-matter>
<book-body>
<book-part id="bid.2" book-part-type="chapter">
<book-part-meta>...</book-part-meta>
<body>
<sec id="bid.3">
<title>History</title>
<p>Initially, GenBank was built and maintained at Los Alamos National
Laboratory (<xref ref-type="kwd" rid="bid.41">LANL</xref>). In the
early 1990s, this responsibility was awarded to NCBI through ...</p>
</sec>
<sec id="bid.4">
<title>International Collaboration</title>
<p>In the mid-1990s, the GenBank database became part of the
International Nucleotide Sequence Database Collaboration with the
EMBL database ...</p>
</sec>
</body>
<back>...</back>
</book-part>
<book-part>...</book-part>
<book-part>...</book-part>
<book-part>...</book-part>
</book-body>
</book>