Flexner, Simon and Helen
MLA
Sergeant, Elizabeth Shepley, 1881-1965. Flexner, Simon and Helen. Box 2, folder 50. 1920-46, n.d.. https://collections.library.yale.edu/catalog/10520873.
APA, 6th edition
Sergeant, Elizabeth Shepley, 1881-1965. (["Box 2, folder 50"])(1920-46, n.d.)[Flexner, Simon and Helen]. https://collections.library.yale.edu/catalog/10520873.