MLA

Wilder, Thornton, 1897-1975. Miscellaneous 1940s. Box 150, folder 3609. n.d.. https://collections.library.yale.edu/catalog/16592075.

APA, 6th edition

Wilder, Thornton, 1897-1975. (["Box 150, folder 3609"])(n.d.)[Miscellaneous 1940s]. https://collections.library.yale.edu/catalog/16592075.