In researching the behavior of cushions, I ran across this gem of a paper written by Professor Moore at the University of Michigan. Most of it was written just before Pearl Harbor, with a post-script from 1947, presumably after Prof Moore returned from a bit of atom-smashing.
A lot of the science can be skimmed over, but many of his non-technical comments regarding the bridge, grip, and stroke are very interesting.
Since I did not see this paper linked at Dr. Dave's or the SF Billiards site, I will provide it here:
MECHANICS OF BILLIARDS, AND ANALYSIS OF WILLIE HOPPE'S STROKE
A. D. MOORE
Professor of Electrical Engineering
College of Engineering
University of Michigan
Ann Arbor, Michigan
January 17, 1942
http://rpetit3.club.fr/Moore/Moore_analysis.pdf