MLA

Wharton, Edith, 1862-1937. "Her Son": holograph manuscript, corrected. Box 17, folder 498-502. n.d.. https://collections.library.yale.edu/catalog/32181862.

APA, 6th edition

Wharton, Edith, 1862-1937. (["Box 17, folder 498-502"])(n.d.)["Her Son": holograph manuscript, corrected]. https://collections.library.yale.edu/catalog/32181862.