More on Sonny, briefly

For those interested in Sonny Umpad's work, he did a book many years ago called Balisong: The Lethal Art of Filipino Knife Fighting. This was co-written by Sid Campbell, a master of Shorin-ryu Karate and a prolific writer, and Gary Cagaanan, a long-time student of Sonny's. This is still in print, and you can see more about it on Amazon.com.