MLA

Sergeant, Elizabeth Shepley, 1881-1965. Bynner, Witter. Box 1, folder 22. 1951-61, n.d.. https://collections.library.yale.edu/catalog/17054222.

APA, 6th edition

Sergeant, Elizabeth Shepley, 1881-1965. (["Box 1, folder 22"])(1951-61, n.d.)[Bynner, Witter]. https://collections.library.yale.edu/catalog/17054222.