I have worked with the Giammetteos. This book is not involved with research, but has fantastic clinical application. Their research tends to be based on clinical experience. In response to Serpa's criticism, exploring similar works were not considered because it's influence is primarily the Jones' Strain CounterStrain (SCS). They merely applied the SCS principles to the many tissues that have smooth muscle. In fact Jones himself sanctioned the references to SCS within the book. As far as I know, no one else has done this, and I am the first one who would like to explore similar work. The names and references in Serpa's response did not provide any substantive Google searches given their foreign publishing.
Most people can self teach themselves with this book, because it presents every technique in easy to view photos, and concise descriptions. It covers a spectrum of different tissue making for many great opportunities to use the techniques. It is a worthwhile book to purchase, and I have used it a lot clinically with good results. I even use it successfully on myself. Thank you.