reference book vs reference work

reference book and reference work both are nouns.

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

As nouns, reference book and reference work are synonyms defined as:

reference book and reference work: a book to which you can refer for authoritative facts

Other synonyms of reference book include book of facts, reference.

reference book (noun)	reference work (noun)
a book to which you can refer for authoritative facts	a book to which you can refer for authoritative facts