I like the Sam Biser books and tapes because Richard Schultz shows how he makes his formulas, and he shows how to do the cold sheet treatment by demonstrating it with someone (along with many other things that aren't coming to mind right away). After reading how to do these things several times, it's really great to see things demonstrated.
I don't have any of the video tapes from Richard Schultz himself, so I don't know if the same demonstrations are on tapes that we can get directly from him. Hopefully someone else can help with this.