MLA

Stein, Gertrude, 1874-1946. Bonney, Therese. Box 98, folder 1887. 1945, n.d.. https://collections.library.yale.edu/catalog/11219349.

APA, 6th edition

Stein, Gertrude, 1874-1946. (["Box 98, folder 1887"])(1945, n.d.)[Bonney, Therese]. https://collections.library.yale.edu/catalog/11219349.