MLA

Eliot, George, 1819-1880. Letter, Wednesday, to Mr. Bray. Box 1. [1856 Dec 2]. https://collections.library.yale.edu/catalog/32471229.

APA, 6th edition

Eliot, George, 1819-1880. (["Box 1"])([1856 Dec 2])[Letter, Wednesday, to Mr. Bray]. https://collections.library.yale.edu/catalog/32471229.