MLA

Denham, John Charles, -1867. Lawrence, Thomas: letter to Mary Denham regarding paintings by her son Henry Hamilton. Box 1, folder 37. circa 1818. https://collections.library.yale.edu/catalog/12384818.

APA, 6th edition

Denham, John Charles, -1867. (["Box 1, folder 37"])(circa 1818)[Lawrence, Thomas: letter to Mary Denham regarding paintings by her son Henry Hamilton]. https://collections.library.yale.edu/catalog/12384818.