MLA

Butts, Mary, 1890-1937. Bagg, Camilla Rodker. Box 1, folder 2. [ca. 1928]-32. https://collections.library.yale.edu/catalog/16893630.

APA, 6th edition

Butts, Mary, 1890-1937. (["Box 1, folder 2"])([ca. 1928]-32)[Bagg, Camilla Rodker]. https://collections.library.yale.edu/catalog/16893630.