MLA

Stein, Gertrude, 1874-1946. Vest. Box 166, folder 4306. n.d.. https://collections.library.yale.edu/catalog/2003132.

APA, 6th edition

Stein, Gertrude, 1874-1946. (["Box 166, folder 4306"])(n.d.)[Vest]. https://collections.library.yale.edu/catalog/2003132.