MLA

Sergeant, Elizabeth Shepley, 1881-1965. Parsons, Alice. Box 6, folder 148. 1921. https://collections.library.yale.edu/catalog/17054228.

APA, 6th edition

Sergeant, Elizabeth Shepley, 1881-1965. (["Box 6, folder 148"])(1921)[Parsons, Alice]. https://collections.library.yale.edu/catalog/17054228.