MLA

Eliot, George, 1819-1880. Letter. Box 9. 1926 Feb 24. https://collections.library.yale.edu/catalog/32365684.

APA, 6th edition

Eliot, George, 1819-1880. (["Box 9"])(1926 Feb 24)[Letter]. https://collections.library.yale.edu/catalog/32365684.