MLA

Wilder, Thornton, 1897-1975. Correspondence. Box 5, folder 108-112. 1935-39. https://collections.library.yale.edu/catalog/17071771.

APA, 6th edition

Wilder, Thornton, 1897-1975. (["Box 5, folder 108-112"])(1935-39)[Correspondence]. https://collections.library.yale.edu/catalog/17071771.