MLA

Nicholls, Norton, 1741?-1809. Thomas Gray to Norton Nicholls. Cambridge. Concerns Charles de Bonstetten; William Johnson Temple. Box 1, folder 107. 1771 May 3. https://collections.library.yale.edu/catalog/17439904.

APA, 6th edition

Nicholls, Norton, 1741?-1809. (["Box 1, folder 107"])(1771 May 3)[Thomas Gray to Norton Nicholls. Cambridge. Concerns Charles de Bonstetten; William Johnson Temple]. https://collections.library.yale.edu/catalog/17439904.