MLA

Simpson, Randolph Linsly, 1927-1992. Studio unknown Full length portrait, seated boy with dog. Tintype, sixth plate. Box 7, folder 95. circa 1870. https://collections.library.yale.edu/catalog/2002152.

APA, 6th edition

Simpson, Randolph Linsly, 1927-1992. (["Box 7, folder 95"])(circa 1870)[Studio unknown Full length portrait, seated boy with dog. Tintype, sixth plate]. https://collections.library.yale.edu/catalog/2002152.