MLA

Eliot, George, 1819-1880. Letter, to Charles Lee Lewes. Box 9. 1883 Dec 28. https://collections.library.yale.edu/catalog/10001383.

APA, 6th edition

Eliot, George, 1819-1880. (["Box 9"])(1883 Dec 28)[Letter, to Charles Lee Lewes]. https://collections.library.yale.edu/catalog/10001383.