On the following link: https://drive.google.com/file/d/1iD0MSbImzfuDgTwIEEF-5J8sLAtTchEQ/view?usp=sharing
Pages 68-71 has a good chronology about hybrid rocketry and how the hobby of rocketry became involved with this technological capability.
A great resource for rocket contest data: http://georgesrockets.com/GRP/GRP-home.htm