MLA

Simpson, Randolph Linsly, 1927-1992. Unknown French photographer "American Red Cross Hospital No. 109" Two troopers visit convalescing comrade in hospital. Photographic postcard. Box 25. circa 1918. https://collections.library.yale.edu/catalog/16189316.

APA, 6th edition

Simpson, Randolph Linsly, 1927-1992. (["Box 25"])(circa 1918)[Unknown French photographer "American Red Cross Hospital No. 109" Two troopers visit convalescing comrade in hospital. Photographic postcard]. https://collections.library.yale.edu/catalog/16189316.