MLA

Wheaton, Joseph, 1755-1828. Graham, George, autograph letter signed to Wheaton. Box 1, folder 11. 1815 October 5. https://collections.library.yale.edu/catalog/32528314.

APA, 6th edition

Wheaton, Joseph, 1755-1828. (["Box 1, folder 11"])(1815 October 5)[Graham, George, autograph letter signed to Wheaton]. https://collections.library.yale.edu/catalog/32528314.