* Richard G. Davis: "Bombing the European Axis Powers: A Historical Digest of the Combined Bomber Offensive, 1939 - 1945" - [http://www.maxwell.af.mil/au/aul/aupress/Davis%20CD/Pages/iib.htm online] | * Richard G. Davis: "Bombing the European Axis Powers: A Historical Digest of the Combined Bomber Offensive, 1939 - 1945" - [http://www.maxwell.af.mil/au/aul/aupress/Davis%20CD/Pages/iib.htm online] |