Cite

German East Africa. Daressalam. D 6 [cartographic material].

MLA

German East Africa. Daressalam. D 6 [Cartographic Material]. Ordnance Survey, 1916. https://collections.library.yale.edu/catalog/15532749.

APA, 6th edition

German East Africa. Daressalam. D 6 [cartographic material]. (1916). [Maps]. Ordnance Survey, https://collections.library.yale.edu/catalog/15532749.