MLA

Service, United States. Army Map. Calais City Plan [Cartographic Material] / Prepared under the Direction of the Chief of Engineers, U.S. Army. 1943. https://collections.library.yale.edu/catalog/15484350.

APA, 6th edition

Service, U. S. A. M. (1943). Calais city plan [cartographic material] / prepared under the direction of the Chief of Engineers, U.S. Army. [Maps]. https://collections.library.yale.edu/catalog/15484350.