In section 17, Stress-Influence Tendency (p21-22), he mentions some final work by Pavlov, but doesn't provide a citation. I spent some time trying to find it when I first read this years ago, but was unable to. I'm wondering whether it's even reliable: I'd think that work by Pavlov could be found with him as an author, rather than in a "popular paperback" written by an un-named psychiatrist. If anyone knows what book…
Daniel Todes' Biography of Pavlov presents some of the material as well.