The young Soviet Union, like any other major power, undertook great efforts to learn from “Great War”. A military comission started publishing a military history of the First World War aimed at the training of Red Army officers. The resulting seven-volume work called Стратегический очерк войны 1914-1918 гг. (Strategic Outline of the War 1914-1918) focuses on strategy and operations and contains a lot of documents, orders and reports. the obvious disadvantage for English speakers is that the work is available in Russian only so far.
The links here lead to HTML versions of the books, including the maps, available at http://www.grwar.ru/library/index.html. Additionally, DJVU versions of all volumes are available at http://www.runivers.ru/lib/book3171/.
Part 1. From the declaration of war to the beginning of September 1914: The first invasion of the Russian armies into East Prussia and the Battle of Galicia. Edited by Tsikhovich Ya. 1922
Part 2. From September 15th to November 25th 1914: The August battle. Warsaw-Ivangorod, Cracow and Łódź operations, operations in Galicia and the Carpathians. Hyrovskoe battle. Edited by G. Korolkov. 1922
Part 3. From November 25th, 1914 to March 28th, 1915. Edited by A. Neznamov. 1922
Part 4. From October 1915 to September 1916: Mackensen’s breakthrough at Gorlice, the struggle for Przemysl and Lviv. The long retreat of the russian Army. Edited by A. Neznamov. 1922
Part 5. October 1915 – September 1916. Trench warfare and attempts to break the Austrian South-Western Front. Edited by VN. Klembowski. M. 1920
Part 6 May 1916 to the end of 1916: Breakthrough of the South-Western Front in May 1916 and operations until the end of the year. Edited by AM. Zayonchkovsky. M. 1923
Part 7. The Campaign of 1917. Edited by AM. Zayonchkovsky. M. 1923