A long time ago I used to study fighting with a tanto, derived loosely from aikijujutsu. Recently I have found myself glancing through a lot of forms practice and analyzing the movements, and was wondering if there are any good references out there to tanto forms. I've found a few online, but many of them don't quite have the right feel to them at least in video form, and so I am looking for some sort of printed reference I can look through and try to better understand.
Art isn't that important, but older forms are preferable.