The ANA library used to loan videos. I remember borrowing a few that described errors & varieties. I suspect that the ANA still has the videos. (All I borrow is the occasional book nowadays). To borrow materials I think you need to be a member of the ANA. If you are not a member, then I recommend you visit www.money.org You can also search for threads here at CT like this one: http://www.cointalk.com/t71726/