MLA

Boswell, James, 1806-1857. Account between Charles Douglas and Hamilton Douglas Boswell. Box 21, folder 620. 1815. https://collections.library.yale.edu/catalog/16645643.

APA, 6th edition

Boswell, James, 1806-1857. (["Box 21, folder 620"])(1815)[Account between Charles Douglas and Hamilton Douglas Boswell]. https://collections.library.yale.edu/catalog/16645643.