A great book about Flintlocks that is worth adding to your library if you do not have it and you have the slightest interest in flintlock firearms is:
The Flintlock, It's origin, Development , and Use by Torsten Lenk and translated by G>A. Urquhart. Originally published in Sweden in 1939. The author retired as Director of the Royal Swedish Armory.
Not only does the book have great information, the photos of antique firearms is awesome!