MLA

Simpson, Randolph Linsly, 1927-1992. Unknown photographer Three quarter portrait, young man, standing with hand on wooden post. Cased tintype, ninth plate. Box 6, folder 78. undated. https://collections.library.yale.edu/catalog/2002135.

APA, 6th edition

Simpson, Randolph Linsly, 1927-1992. (["Box 6, folder 78"])(undated)[Unknown photographer Three quarter portrait, young man, standing with hand on wooden post. Cased tintype, ninth plate]. https://collections.library.yale.edu/catalog/2002135.