MLA

Eliot, George, 1819-1880. Beneke, Miss. Box 1. 1880 Mar 19. https://collections.library.yale.edu/catalog/17298270.

APA, 6th edition

Eliot, George, 1819-1880. (["Box 1"])(1880 Mar 19)[Beneke, Miss]. https://collections.library.yale.edu/catalog/17298270.