MLA

Boswell, James, 1806-1857. Douglas, Charles. Box 3, folder 109-127. 1783-98. https://collections.library.yale.edu/catalog/11864301.

APA, 6th edition

Boswell, James, 1806-1857. (["Box 3, folder 109-127"])(1783-98)[Douglas, Charles]. https://collections.library.yale.edu/catalog/11864301.