MLA

Simpson, Randolph Linsly, 1927-1992. Studio Unknown Full length portrait of William Douglass; elderly man seated in suit with plaid trousers. Cabinet photograph. Box 9, folder 215. circa 1875. https://collections.library.yale.edu/catalog/2002267.

APA, 6th edition

Simpson, Randolph Linsly, 1927-1992. (["Box 9, folder 215"])(circa 1875)[Studio Unknown Full length portrait of William Douglass; elderly man seated in suit with plaid trousers. Cabinet photograph]. https://collections.library.yale.edu/catalog/2002267.