Internet and books. Why? Also, if you are implying I am trusting amateurs, then you are wrong. I'm not an idiot. I don't trust people just because they have a "martial arts" video. For instance, the guy in the link I gave has been practicing Jui-jitsu for 30 years, has learned it both in the army and law inforcement. Also, as I said, I also am currently taking Jui-jitsu at a dojo as well.