I strongly recommend Sasuga Books, a specialty store in the Boston area. They have at www.sasugabooks.com
. Karen, the store manager, has been very helpful in locating Japanese martial arts books which are not in their extensive stock. She even fixed me up with a subscription to Kodokan Judo Magazine for six months during their last Olympic coverage. IF you can't find what you're looking for in their online catalog, give them a call.