MLA

Johnson, James Weldon, 1871-1938. Johnsons, W.E.B. Du Bois, Nina Du Bois, John B. Nail, John E. Nail and Grayce Fairfax Nail, Great Barrington, Massachusetts. Box 109, folder 960. circa 1928. https://collections.library.yale.edu/catalog/15814939.

APA, 6th edition

Johnson, James Weldon, 1871-1938. (["Box 109, folder 960"])(circa 1928)[Johnsons, W.E.B. Du Bois, Nina Du Bois, John B. Nail, John E. Nail and Grayce Fairfax Nail, Great Barrington, Massachusetts]. https://collections.library.yale.edu/catalog/15814939.