MLA

Van Thal, Herbert, 1904-1983. Painter, George. Box 1, folder 90. n.d.. https://collections.library.yale.edu/catalog/16545994.

APA, 6th edition

Van Thal, Herbert, 1904-1983. (["Box 1, folder 90"])(n.d.)[Painter, George]. https://collections.library.yale.edu/catalog/16545994.