Authorities and Textbook

Authorities noun - The organization that is the governing authority of a political unit.

Textbook and authorities are semantically related. in expert topic. In some cases you can use "Textbook" instead a noun "Authorities".

Textbook noun - A book used for instruction in a subject.

Authorities and textbook are semantically related. Sometimes you can replace term "Authorities" with "Textbook", this nouns are similar.