source book vs reference book

source book and reference book both are nouns.

Word	Noun	Adjective	Verb	Adverb
source book	Yes	No	No	No
reference book	Yes	No	No	No

As nouns, reference book is a hypernym of source book; that is, reference book is a word with a broader meaning than source book:

source book: a collection of historically important documents published together as a book
reference book: a book to which you can refer for authoritative facts

Other hypernyms of source book include book of facts, reference, reference work.

source book (noun)	reference book (noun)
a collection of historically important documents published together as a book	a book to which you can refer for authoritative facts