MLA

Farrar, John Chipman, 1896-1974. Farrar, Margaret. Box 39. 1954-1960, undated. https://collections.library.yale.edu/catalog/10729366.

APA, 6th edition

Farrar, John Chipman, 1896-1974. (["Box 39"])(1954-1960, undated)[Farrar, Margaret]. https://collections.library.yale.edu/catalog/10729366.