Container element for the various title elements that might be used for the work
<!ELEMENT book-title-group %book-title-group-model; >
(book-title, subtitle*, trans-title-group*, alt-title*)
The following, in order:
<book>
<book-meta>
<book-id pub-id-type="other">emdocrin</book-id>
<book-title-group>
<book-title>Endocrinology</book-title>
<subtitle>An Integrated Approach</subtitle>
</book-title-group>
...</book-meta>
<book-front>...</book-front>
<body>...</body>
<back>...</back>
</book>
bookmeta3.ent