How about Merriam-Webster Dictionary
Authoritative: having or proceeding from authority
Authority: (1): a citation (as from a book or file) used in defense or support (2): the source from which the citation is drawn b (1): a conclusive statement or set of statements
Is it an authoritative text?
Pat Kennedy, CFEI, CFPS, MIFireE
Fire and Explosion Analyst
Sarasota, Florida
[
www.kennedy-fire.com]