"Imslp has lots, as do I, and many members here who like to share such things....
I got some also from Delcamp guitar also. If you know what in particular you are looking for, Im sure someone here can help you find it.
"Richard Taruskin states, for example:
"Oral" practices that we know only imperfectly if at all - for example, the use of chord- strumming instruments in unwritten musical repertoires and their effect in reconditioning musical…"