Crossborders provides baptisms, marriages and deaths from the Kriegsarchiv [Oesterreichisches Staatsarchiv] for the Feldsuperiorat Wien. It includes individuals from many areas of the Austro-Hungarian Empire. These are images of the original church books. Also available on this site are Kriegs Matriken 1914-1920 [military marrigages and deaths]; Vienna church records, and Franziszeischen Kataster.
Articles regarding Austrian Military records can be found in the FEEFS Journal. Some of these are online at: Foundation for Eastern European Family History. See Vol. IV (2001) and article by Steven Blodgett at this link: "Recruiting Soldiers into the Austrian Army". [broken links]