MLA

Nicholls, Norton, 1741?-1809. Charles de Bonstetten to Norton Nicholls. Cambridge. Concerns Thomas Gray; John Wheler. Box 1, folder 87. 1770 Feb 6. https://collections.library.yale.edu/catalog/17439884.

APA, 6th edition

Nicholls, Norton, 1741?-1809. (["Box 1, folder 87"])(1770 Feb 6)[Charles de Bonstetten to Norton Nicholls. Cambridge. Concerns Thomas Gray; John Wheler]. https://collections.library.yale.edu/catalog/17439884.