is a very comprehensive but
ugly site. The link page from this site provides what is most likely a
complete list of superiors.
The newsgroup: alt.music.leonard-cohen
As far as info, you'll want to mention that Bob did back-up vocals on a Leonard album and also use Leonard's succinct description of Bob and his relationship to Bob which I've seen reprinted in "Wanted Man" edited by John Bauldie.
You might also want to mention that everyone should at least own Leonard's first album, "Songs of Leonard Cohen."