MLA

Emerson, Thomas I. (Thomas Irwin), 1907-1991. Drafts. Box 92, folder 115 - 117. Undated. https://collections.library.yale.edu/catalog/10021569.

APA, 6th edition

Emerson, Thomas I. (Thomas Irwin), 1907-1991. (["Box 92, folder 115 - 117"])(Undated)[Drafts]. https://collections.library.yale.edu/catalog/10021569.