A string of natural language text mentioned in some bibliographic reference. Texts are distinguished from strings in general because they may be treated specially in some databases, or presented as free-flowing text to a human reader. BIBLIO-NL-TEXT's are used for different purposes than biblio-names. BIBLIO-NL-TEXT's are for things like notes and abstracts; BIBLIO-NAME's are meant to identify some object or some property.
(=> (Ref.Notes $X $Y) (Biblio-Nl-Text $Y)) (=> (Ref.Abstract $X $Y) (Biblio-Nl-Text $Y))