Thanks for posting that. I think I had a digital copy squirreled away somewhere, but it's nice to find.
Unfortunately, scholarly works on firearm ballistics seem a bit scarce. This is especially true of internal ballistics, which interest me the most(not surprising given my chemistry back ground) but which don't seem to be out there.
Sharpe's book is one of the best references I've found, but even then it's not as detailed as I'd like. Hatcher's Notebook also has a lot of good information.