MLA

of Strategic Services. Research, United States. Office, and Analysis Branch. Germany, Wehrkreise [Military District] Boundaries / Compiled and Drawn in the Branch of Research and Analysis, OSS. OSS, 1943. https://collections.library.yale.edu/catalog/15479638.

APA, 6th edition

of Strategic Services. Research, U. S. O., & Branch, A. (1943). Germany, Wehrkreise [military district] boundaries / compiled and drawn in the Branch of Research and Analysis, OSS. [Maps]. OSS, https://collections.library.yale.edu/catalog/15479638.