What has the author Othmar Hackl written?

Othmar Hackl has written:

'Die bayerische Kriegsakademie (1867-1914)' -- subject(s): History, History, Military, Kriegsakademie (Bavaria, Germany), Military History, Military education

'Der bayerische Generalstab (1792-1919)' -- subject(s): Bavaria (Germany), Bavaria (Germany). Heer, Generals, History, Military, Military History, Officers