MLA

Stettheimer, Florine, 1871-1944. Bernheimer, Louis. Box 1, folder 8. 1922, n.d.. https://collections.library.yale.edu/catalog/15729081.

APA, 6th edition

Stettheimer, Florine, 1871-1944. (["Box 1, folder 8"])(1922, n.d.)[Bernheimer, Louis]. https://collections.library.yale.edu/catalog/15729081.