A.M.S. (Series) ; L751. "Type F (AMS 1), 1947". Transverse Mercator projection. "Prepared under the direction of the Chief of Engineers by the Army Map Service (AM), Corps of Engineers, Department of the Army, Washington, D.C. Compiled in 1947 from Korea 1:50,000, Japanese Imperial Land Survey, Ipsŏng-ni, 1940. Planimetric detail partially revised from aerial photography by photo-planimetric methods. Aerial photography 1945."