I think there are obligations for authors and publishers to produce a reference book or textbook? We are worried that our students use books that are not reliable reference books.
Yes, you are correct "from a librarian's point of view" as any library of some mention an academic institution necessarily has a Reference Section wherein one can find all that material you have mentioned. But, a reference book means a book based on research. It may be theoretical as an evaluation or review of some theory or philosophy. It may also be a research contribution to answer a problem. Since these books may be referred in further research work, these are called reference books. The books written from the point of view of students on the material already known and problem solved to help them to do their course work are called Textbooks as sometimes these are prescribed. Thus, original contribution and compilation of material (definitely in a more difficult language or a complex way of presentation or in a simple and easy language with simplicity of presentation of material) are the criteria to distinguish text and reference books. However, sometime a textbook written by an authority may turn into a reference book.