MLA

Wharton, Edith, 1862-1937. Letters. Box 64, folder 1790-92. 1881-1924. https://collections.library.yale.edu/catalog/2013855.

APA, 6th edition

Wharton, Edith, 1862-1937. (["Box 64, folder 1790-92"])(1881-1924)[Letters]. https://collections.library.yale.edu/catalog/2013855.