MLA

Wilder, Thornton, 1897-1975. Hutchins, Robert. Box 43, folder 1118-1122. 1931-75, n.d.. https://collections.library.yale.edu/catalog/17056650.

APA, 6th edition

Wilder, Thornton, 1897-1975. (["Box 43, folder 1118-1122"])(1931-75, n.d.)[Hutchins, Robert]. https://collections.library.yale.edu/catalog/17056650.