Anna, ylou might want to try and buy newer books, Datig and Jones are nice, but they are 50 years out of date
If you just have the one Kreighoff, you may not want to buy Gibson's book on Kreighoff or the Simson Luger book for the one Simson, but I'd look for either Imperial Lugers (out of print) by Jan Still or his new book coming out very soon Central Powers. he also wrote Weimar Lugers and Third Reich Lugers (seperate books).
Ed
PS: a scanner works "ok" but not wonderful. It can give an idea and sometimes fairly clear pictures. Resolution can be set to say 70 or a 100 and then crop down the photo.