Southeastern Europe [cartographic material] / lithographed in Reproduction Branch, OSS.
MLA
of Strategic Services. Research, United States. Office, and Analysis Branch. Southeastern Europe [Cartographic Material] / Lithographed in Reproduction Branch, OSS. OSS, 0AD. https://collections.library.yale.edu/catalog/15506464.
APA, 6th edition
of Strategic Services. Research, U. S. O., & Branch, A. (0 C.E.). Southeastern Europe [cartographic material] / lithographed in Reproduction Branch, OSS. [Topographic maps]. OSS, https://collections.library.yale.edu/catalog/15506464.