MLA

Simpson, Randolph Linsly, 1927-1992. Studio unknown Bust length cameo portrait of man in suit. Cabinet photograph. Box 9, folder 227. circa 1870. https://collections.library.yale.edu/catalog/2002279.

APA, 6th edition

Simpson, Randolph Linsly, 1927-1992. (["Box 9, folder 227"])(circa 1870)[Studio unknown Bust length cameo portrait of man in suit. Cabinet photograph]. https://collections.library.yale.edu/catalog/2002279.