MLA

Eliot, George, 1819-1880. Letter, to Elinor Ouvry. Box 8. [1928] Apr 3. https://collections.library.yale.edu/catalog/10001298.

APA, 6th edition

Eliot, George, 1819-1880. (["Box 8"])([1928] Apr 3)[Letter, to Elinor Ouvry]. https://collections.library.yale.edu/catalog/10001298.