MLA

Simpson, Randolph Linsly, 1927-1992. Full length double portrait J. Luther Spencer and shoe shine boy; man in top hat, seated right; black boy kneeling left, with equipment of his trade, barefoot. Tintype, quarter plate. Box 7, folder 133. circa 1876. https://collections.library.yale.edu/catalog/2002189.

APA, 6th edition

Simpson, Randolph Linsly, 1927-1992. (["Box 7, folder 133"])(circa 1876)[Full length double portrait J. Luther Spencer and shoe shine boy; man in top hat, seated right; black boy kneeling left, with equipment of his trade, barefoot. Tintype, quarter plate]. https://collections.library.yale.edu/catalog/2002189.