Cite

Africa 1:63 360. Pemba Island [cartographic material] / drawn and printed at the Ordnance Survey Office, Southampton, 1913.

MLA

Survey, Great Britain. Ordnance. Africa 1:63 360. Pemba Island [Cartographic Material] / Drawn and Printed at the Ordnance Survey Office, Southampton, 1913. Ordnance Survey Office, 1913. https://collections.library.yale.edu/catalog/15532775.

APA, 6th edition

Survey, G. B. O. (1913). Africa 1:63 360. Pemba Island [cartographic material] / drawn and printed at the Ordnance Survey Office, Southampton, 1913. [Maps]. Ordnance Survey Office, https://collections.library.yale.edu/catalog/15532775.