Cite

South East Europe, ethnographical map [cartographic material].

MLA

Section, Great Britain. War Office. General Staff. Geographical. South East Europe, Ethnographical Map [Cartographic Material]. War Office, 1918. https://collections.library.yale.edu/catalog/15238226.

APA, 6th edition

Section, G. B. W. O. G. S. G. (1918). South East Europe, ethnographical map [cartographic material]. [Maps]. War Office, https://collections.library.yale.edu/catalog/15238226.