Letter : to an unidentified recipient
MLA
Stowe, Harriet Beecher, 1811-1896. Letter : to an unidentified recipient. Box 34, folder GROUP 567, F-3. n.d.. https://collections.library.yale.edu/catalog/32308136.
APA, 6th edition
Stowe, Harriet Beecher, 1811-1896. (["Box 34, folder GROUP 567, F-3"])(n.d.)[Letter : to an unidentified recipient]. https://collections.library.yale.edu/catalog/32308136.