Robert, do you own the Osprey Aviation Elite volume about the Schlachtflieger too?
this one contains more info about the Schlachtflieger arm, its creation, its units and its operations, but just as the Classic volume, it is only a starting point.
should you have any special interest within the topic of the Schlachtflieger, feel free to post them, I will try to point out some more books of interest for you then
cheers
phil