Corvo and Flores / compiled and drawn at War Office.
MLA
Section, Great Britain. War Office. General Staff. Geographical. Corvo and Flores / Compiled and Drawn at War Office. Army Map Service, U. S. Army, 1942. https://collections.library.yale.edu/catalog/15249355.
APA, 6th edition
Section, G. B. W. O. G. S. G. (1942). Corvo and Flores / compiled and drawn at War Office. [Maps]. Army Map Service, U. S. Army, https://collections.library.yale.edu/catalog/15249355.