Roderich Cescotti, Kampfflugzeuge und Aufklärer: Entwicklung, Produktion, Einsatz und zeitgeschichtliche Rahmenbedingungen von 1935 bis heute, Deutsche Luftfahrt 15, Koblenz: Bernard & Graefe, 1989, ISBN978-3-7637-5293-5, p. 100(tiếng Đức)
Roy Godson and James J. Wirtz, Strategic Denial and Deception: The Twenty-First Century Challenge, New Brunswick, New Jersey: Transaction, 2002, ISBN978-0-7658-0113-5, p. 61.
Barton Whaley, Covert German Rearmament, 1919–1939: Deception and Misperception, Foreign Intelligence Book Series, Frederick, Maryland: University Publications of America, 1984, ISBN978-0-89093-542-2, p. 43: "[When Conrad Patzig was appointed head of the Abwehr on ngày 7 tháng 6 năm 1932], its strategic aerial photoreconnaissance was still little more than Theodor Rowehl's one-man show."
Michael Holm. “Aufklärungsgruppe Ob.d.L.”. Air units → Reconnaissance units (bằng tiếng Anh). Сайт «The Luftwaffe, 1933—45». Truy cập ngày 3 tháng 5 năm 2016.