MLA

Simpson, Randolph Linsly, 1927-1992. Unknown photographer Full length portrait, young soldier wearing kepi. Cased tintype, sixth plate. Box 6, folder 82. circa 1868. https://collections.library.yale.edu/catalog/2002139.

APA, 6th edition

Simpson, Randolph Linsly, 1927-1992. (["Box 6, folder 82"])(circa 1868)[Unknown photographer Full length portrait, young soldier wearing kepi. Cased tintype, sixth plate]. https://collections.library.yale.edu/catalog/2002139.