MLA

Cooper, James Fenimore, 1789-1851. Griswold, Rufus Wilmot. Box 13, folder 360. 1851. https://collections.library.yale.edu/catalog/17073668.

APA, 6th edition

Cooper, James Fenimore, 1789-1851. (["Box 13, folder 360"])(1851)[Griswold, Rufus Wilmot]. https://collections.library.yale.edu/catalog/17073668.