MLA

Wharton, Edith, 1862-1937. Correspondence. Box 40, folder 1217-21. 1918. https://collections.library.yale.edu/catalog/17401372.

APA, 6th edition

Wharton, Edith, 1862-1937. (["Box 40, folder 1217-21"])(1918)[Correspondence]. https://collections.library.yale.edu/catalog/17401372.