A.M.S. (Series) ; L751. "Sixth Edition-AMS (FEC)". "Prepared under the direction of the Chief of Engineers by the Army Map Service (PT), U.S. Army, Washington, D.C. Redrawn in 1946 from Korea, 1:50,000, Japanese Imperial Land Survey, Kosan, 1937.... Planimetric detail checked in 1950 from aerial photography dated 1947 by photo-planimetric methods by the 64th Engineer Base Topographic Battalion.... Road classifications revised in May 1951 by the 64th Engineer Base Topographic Battalion form reconnaissance material furnished by the Engineer, EUSAK. Sino-Korean place name characters added in 1951 by 64th Engineer Base Topographic Battalion."