MLA

of Economic Warfare, United States. Board. Spain and Portugal [Cartographic Material] / Board of Economic Warfare ; Drawn in R. and A., OSS. OSS, 1943. https://collections.library.yale.edu/catalog/15487317.

APA, 6th edition

of Economic Warfare, U. S. B. (1943). Spain and Portugal [cartographic material] / Board of Economic Warfare ; drawn in R. and A., OSS. [Maps]. OSS, https://collections.library.yale.edu/catalog/15487317.