MLA

Simpson, Randolph Linsly, 1927-1992. Studio unknown Two men elegantly dressed, one standing, the other seated with bowler hat and cane. Tintype, sixth plate. Box 7, folder 140. circa 1875. https://collections.library.yale.edu/catalog/2002204.

APA, 6th edition

Simpson, Randolph Linsly, 1927-1992. (["Box 7, folder 140"])(circa 1875)[Studio unknown Two men elegantly dressed, one standing, the other seated with bowler hat and cane. Tintype, sixth plate]. https://collections.library.yale.edu/catalog/2002204.