Map showing Allied progress on the front between Arras and the Aisne [cartographic material].
MLA
Office, Great Britain. War. Map Showing Allied Progress on the Front between Arras and the Aisne [Cartographic Material]. War Office, 1917. https://collections.library.yale.edu/catalog/15237904.
APA, 6th edition
Office, G. B. W. (1917). Map showing Allied progress on the front between Arras and the Aisne [cartographic material]. [Maps]. War Office, https://collections.library.yale.edu/catalog/15237904.