You might want to add the 25th Gun Digest Treasury as that contains the articles on Gun Proof by Lee Kennett. They contain the proof information on Czechoslavakia,Austria-Hungary France and Spain.You can probably find the Treasury on e-Bay or ABEbooks.com.I would recommend e-Bay as Abebooks.com have changed some time ago to a system that requires you to go through a clearing house to place an order,denying you contact with the actual seller.I think that the system was changed to control the flow of money and stop any "stiffing " by the book sellers. I generally want to talk to the book shop when buying a used book so as to learn all paticulars about the book. I don't use ABEbooks much anymore.
Best Regards
Gene