MLA

Eliot, George, 1819-1880. Letter. Box 9. 1925 Jan 18. https://collections.library.yale.edu/catalog/32365683.

APA, 6th edition

Eliot, George, 1819-1880. (["Box 9"])(1925 Jan 18)[Letter]. https://collections.library.yale.edu/catalog/32365683.