MLA

Nicholls, Norton, 1741?-1809. Norton Nicholls to Jane Floyer Nicholls. Alloa House. Concerns Scotland; John Erskine. Box 2, folder 220. 1774 Jul 10. https://collections.library.yale.edu/catalog/17440017.

APA, 6th edition

Nicholls, Norton, 1741?-1809. (["Box 2, folder 220"])(1774 Jul 10)[Norton Nicholls to Jane Floyer Nicholls. Alloa House. Concerns Scotland; John Erskine]. https://collections.library.yale.edu/catalog/17440017.