John B. Wilson, Maneuver and Firepower: The Evolution of Divisions and Separate Brigades (1998)
“ Shortly thereafter Pershing revised the replacement system for the AEF. Instead of relying on a replacement and school division and a base and training division for each army corps, he split the replacement function between the army corps and the "communications zone," the area immediately behind the battlefield controlled by the "Service of the Rear." In the communications zone a depot (base and training) division would process personnel into the theater, while a replacement (replacement and school) division in each army corps distributed new personnel to their units. ”
