A map of Northwestern United States and neighboring Canadian Provinces / prepared in the Cartographic Section of the National Geographic Society for the National geographic magazine ; James M. Darley, chief cartographer.
MLA
National Geographic Society (U.S.). Cartographic Section. A map of Northwestern United States and neighboring Canadian Provinces / prepared in the Cartographic Section of the National Geographic Society for the National geographic magazine ; James M. Darley, chief cartographer.. BRBL_00536. 1941. https://collections.library.yale.edu/catalog/15812975.
APA, 6th edition
National Geographic Society (U.S.). Cartographic Section. (["BRBL_00536"])(1941)[A map of Northwestern United States and neighboring Canadian Provinces / prepared in the Cartographic Section of the National Geographic Society for the National geographic magazine ; James M. Darley, chief cartographer.]. https://collections.library.yale.edu/catalog/15812975.