MLA

Section, Great Britain. War Office. General Staff. Geographical. Province of Chih-Li, Southern Sheet [Cartographic Material]. Geographical Section, General Staff, 1909. https://collections.library.yale.edu/catalog/15827231.

APA, 6th edition

Section, G. B. W. O. G. S. G. (1909). Province of Chih-li, southern sheet [cartographic material]. [Maps]. Geographical Section, General Staff, https://collections.library.yale.edu/catalog/15827231.