MLA

Wharton, Edith, 1862-1937. Lapsley, Gaillard. Box 29, folder 868. 1916-31. https://collections.library.yale.edu/catalog/32182661.

APA, 6th edition

Wharton, Edith, 1862-1937. (["Box 29, folder 868"])(1916-31)[Lapsley, Gaillard]. https://collections.library.yale.edu/catalog/32182661.