MLA

Eliot, George, 1819-1880. Letter. Box 8. 1932 Oct 23. https://collections.library.yale.edu/catalog/10001374.

APA, 6th edition

Eliot, George, 1819-1880. (["Box 8"])(1932 Oct 23)[Letter]. https://collections.library.yale.edu/catalog/10001374.