MLA

Wilder, Thornton, 1897-1975. Correspondence. Box 6, folder 120-121. 1943. https://collections.library.yale.edu/catalog/17418511.

APA, 6th edition

Wilder, Thornton, 1897-1975. (["Box 6, folder 120-121"])(1943)[Correspondence]. https://collections.library.yale.edu/catalog/17418511.