MLA

Boswell, James, 1740-1795. "Attorney". Box 79, folder 1554. n.d.. https://collections.library.yale.edu/catalog/11977883.

APA, 6th edition

Boswell, James, 1740-1795. (["Box 79, folder 1554"])(n.d.)["Attorney"]. https://collections.library.yale.edu/catalog/11977883.