GSGS (Series) ; 2957. Third edition - AMS 1. Conical orthomorphic projection with two standard parallels. "Published at the War Office, 1931. First AMS Printing 1941. Third GSGS Edition, 1939-AMS 1, 1942." "Compiled and drawn at W.O., heliographed at O.S. and printed at W.O. 1939."
