MLA

Zilboorg, James, 1892-1968. Braunstein, David. Box 1, folder 6. 1910s, 1927, undated. https://collections.library.yale.edu/catalog/17096127.

APA, 6th edition

Zilboorg, James, 1892-1968. (["Box 1, folder 6"])(1910s, 1927, undated)[Braunstein, David]. https://collections.library.yale.edu/catalog/17096127.