MLA

General Drafting Company, inc. Military Map of Europe [Cartographic Material] / Compiled from the Most Authentic Sources. General Drafting Co., 0AD. https://collections.library.yale.edu/catalog/15237900.

APA, 6th edition

General Drafting Company, inc. (0 C.E.). Military map of Europe [cartographic material] / compiled from the most authentic sources. [Maps]. General Drafting Co., https://collections.library.yale.edu/catalog/15237900.