MLA

Section, Great Britain. War Office. General Staff. Geographical. Cable Map of the World [Cartographic Material]. War Office, 1909. https://collections.library.yale.edu/catalog/16664845.

APA, 6th edition

Section, G. B. W. O. G. S. G. (1909). Cable map of the world [cartographic material]. [Maps, World maps]. War Office, https://collections.library.yale.edu/catalog/16664845.