Material published with a book but following the narrative flow, for example, appendices and lists of references.
Usage: Back matter typically contains supporting material such as an appendix, acknowledgment, glossary, or bibliographic reference list. In this Tag Set, this element differs from the <back> element in being able to contain book parts (<book-part>).
<!ELEMENT book-back %book-back-model; >
(app | app-group | floats-group | index | index-group | ref-list | book-part | xi:include | ack | bio | dedication | fn-group | glossary | toc | toc-group | notes)+
One or more of any of:
<book dtd-version="1.0">
<book-meta>...</book-meta>
<book-body>...</book-body>
<book-back>
<ack id="bid.394">
<title>Acknowledgments</title>
<p>We gratefully acknowledge the work of Vladimir Soussov,
as well as the entire NCBI Entrez team, especially Grisha
Starchenko, Vladimir Sirotinin, Alexey Iskhakov, Anton
Golikov, and Pramod Paranthaman. We thank Jim Ostell for
guidance, ...</p>
</ack>
<ref-list>...</ref-list>
</book-back>
</book>