MILITARY INTELLIGENCE SERVICE, WAR DEPARTMENT, WASHINGTON D. C. SPECIAL SERIES No. 3 German Military Training, September 17, 1942 "The information summarized here is based on a variety of sources: on German manuals, on technical articles in German military reviews, and above all on the detailed reports of United States observers who saw the German Army at close range in its work of preparing for this war and during the first 2 years of conflict." Digitized by AHEC (U.S. Army Heritage Collections)
http://www.ahco.army.mil