Листы квадрата O-40 американских карт серии N501. Масштаб 1:250,000. Листы карт изданы в 1948-1954 годах. Prepared by the Army Map Service (LU), Corps of Engineers, U.S. Army, Washington, D.C. Eastern Europe. Edition 2-AMS Series N501. Scale 1:250,000. Compiled from the maps of U.S.S.R., 1:100,000, General Staff of the Red Army, 1934-39.