MLA

Nicholls, Norton, 1741?-1809. Norton Nicholls to Jane Floyer Nicholls. Eton. Concerns Eton College; Edward Barnard. Box 1, folder 12. 1756 Oct 24. https://collections.library.yale.edu/catalog/17439809.

APA, 6th edition

Nicholls, Norton, 1741?-1809. (["Box 1, folder 12"])(1756 Oct 24)[Norton Nicholls to Jane Floyer Nicholls. Eton. Concerns Eton College; Edward Barnard]. https://collections.library.yale.edu/catalog/17439809.