MLA

Eliot, George, 1819-1880. Letter, to Lady Burne-Jones. Box 8. 1880 Dec 22. https://collections.library.yale.edu/catalog/10001308.

APA, 6th edition

Eliot, George, 1819-1880. (["Box 8"])(1880 Dec 22)[Letter, to Lady Burne-Jones]. https://collections.library.yale.edu/catalog/10001308.