To my knowledge, this is the first time that this document has seen the light of day. There are a couple references to this article but never has it been made available to the general public. It's all in German and deserves to be translated. But, even with translation this is a pretty important document. See my notes:
This plate has the most interesting air gun. Number 4 is identified in the notes as an Austrian Military Repeater model 1790.
Closeup of gun #4. Clearly this is a Girandoni-style repeater air gun. But, most important is that this one actually looks like an Austrian military weapon, unlike the impostors being pushed by Beeman and company. The trigger guard on this air gun is exactly like other Austrian military rifles of the same period. I think that this is the first picture of what may be a legit Austrian Army Girandoni.