Cite

Belgium and the north east of France G.S.G.S. 2517 [cartographic material].

MLA

Section, Great Britain. War Office. General Staff. Geographical. Belgium and the North East of France G.S.G.S. 2517 [Cartographic Material]. Geographical Section, General Staff, 1910. https://collections.library.yale.edu/catalog/15826827.

APA, 6th edition

Section, G. B. W. O. G. S. G. (1910). Belgium and the north east of France G.S.G.S. 2517 [cartographic material]. [Maps]. Geographical Section, General Staff, https://collections.library.yale.edu/catalog/15826827.