MLA

Section, Great Britain. War Office. General Staff. Geographical. Ajaccio, Plan of Port [Cartographic Material] / Drawn by War Office, 1943. Army Map Service, U.S. Army, 1943. https://collections.library.yale.edu/catalog/15487208.

APA, 6th edition

Section, G. B. W. O. G. S. G. (1943). Ajaccio, plan of port [cartographic material] / Drawn by War Office, 1943. [Maps]. Army Map Service, U.S. Army, https://collections.library.yale.edu/catalog/15487208.