U.S. Department of Defense 
German Campaign in Russia: Planning and Operations (1940-1942) [EPUB ebook] 
WW2: Strategic & Operational Planning: Directive Barbarossa, The Initial Operations, German Attack on Moscow, Offensive in the Caucasus & Battle for Stalingrad

The aim of this edition is to present in a comprehensive way the strategy and military operations of the German army in the attack on Russia in World War 2. The narrative starts with Hitler’s initial plans for an invasion of Russia and ends at the time of Germany’s maximum territorial gains during the battle for Stalingrad.
Contents:
Strategic Planning
Operational Planning
The Initial Operations (22 June-31 July 1941)
Planning for Future Operations
The Diversion and Reassembly
The German Attack on Moscow
The Russian Counteroffensive (December 1941-February 1942)
Preliminary Planning for a German Offensive in the Caucasus, 1942
Preparations for the German Summer Offensive
Initial Operations and New Plans (July 1942)
The Period of Stagnation (August-October 1942)
Critical Analysis of the German Summer Offensive in 1942
List of German Military Leaders (July 1940-November 1942)
Chronology of the Events