External module in the Book Tag Set (and Collection Tag Set) that defines chapter-level/part-level metadata elements and textual elements used in such book components
Book-level metadata elements are declared in a separate module, %bookmeta.ent;.
<!ENTITY % bookpart.ent PUBLIC "-//NLM//DTD NCBI Book DTD Book Component Metadata Elements v3.0 20080202//EN" "bookpart3.ent" >
bookcustom-modules3.ent