Sources

In no particular order:

Facing Violence by Rory Miller
Meditations on Violence by Rory Miller
Drills by Rory Miller
Infighting by Rory Miller
Joint Locks by Rory Miller
No Nonsense Self Defense (website) by Marc MacYoung
The Way of Kata by Lawrence A Kane and Kris Wilder
Conceptual Physics by Paul G. Hewitt
The Bible of Karate (Bubishi) translated with commentary by Patrick McCarthy
Karate My Art by Motobu Choki with compilation and translation by Patrick and Yuriko McCarthy
The Zen Way to the Martial Arts by Taisen Deshimaru
The Essence of Okinawan Karate-Do by Shoshin Nagamine
Karate-do Kyohan by Gichin Funakoshi
An Introduction to General Systems Thinking by Gerald M. Weinberg