MLA

Van Thal, Herbert, 1904-1983. Harding, James. Box 1, folder 56. 1965-79, n.d.. https://collections.library.yale.edu/catalog/16545960.

APA, 6th edition

Van Thal, Herbert, 1904-1983. (["Box 1, folder 56"])(1965-79, n.d.)[Harding, James]. https://collections.library.yale.edu/catalog/16545960.