MLA

National Geographic Society (U.S.). Cartographic Section. Union of Soviet Socialist Republics International boundaries according to Russian treaties and claims as of October 1, 1944 ; Boundaries of January 1, 1938, are shown in red Compiled and drawn in the Cartographic Section of the National Geographic Society. BRBL_00101. c1944.. https://collections.library.yale.edu/catalog/15471602.

APA, 6th edition

National Geographic Society (U.S.). Cartographic Section. (["BRBL_00101"])(c1944.)[Union of Soviet Socialist Republics International boundaries according to Russian treaties and claims as of October 1, 1944 ; Boundaries of January 1, 1938, are shown in red Compiled and drawn in the Cartographic Section of the National Geographic Society]. https://collections.library.yale.edu/catalog/15471602.