Is there some preferred way to list an item in the AMS Open Math Notes series in a bibliography? (See: https://www.ams.org/open-math-notes)
I'm asking about what information should be included, not the particular format of the bibliography.
The issue is that these items are on-line, downloadable pdf's, described as "works in progress", and often course notes.
The 1st thing is you should precisely know what do you want to quote. There are many reference books for mathematicians. Please ask your supervisor about one of them. The book (textbook is enough if some topis is classical) seems to be considerably better from internet.