MLA

Simpson, Evelyn Mary Spearing, 1885-1963. Watson, George. Box 3, folder 82. 1953 17 Oct. https://collections.library.yale.edu/catalog/16828718.

APA, 6th edition

Simpson, Evelyn Mary Spearing, 1885-1963. (["Box 3, folder 82"])(1953 17 Oct)[Watson, George]. https://collections.library.yale.edu/catalog/16828718.