External module in the Book Tag Set (and Collection Tag Set) that defines book-level metadata elements
Metadata elements for book components are declared in a separate module, %bookpart.ent;.
<!ENTITY % bookmeta.ent PUBLIC "-//NLM//DTD NCBI Book DTD Book Metadata Elements v3.0 20080202//EN" "bookmeta3.ent" >
bookcustom-modules3.ent