MLA

Sergeant, Elizabeth Shepley, 1881-1965. Collier, John. Box 1, folder 28-30. 1932-65, n.d.. https://collections.library.yale.edu/catalog/10520872.

APA, 6th edition

Sergeant, Elizabeth Shepley, 1881-1965. (["Box 1, folder 28-30"])(1932-65, n.d.)[Collier, John]. https://collections.library.yale.edu/catalog/10520872.