MLA

Van Thal, Herbert, 1904-1983. "A" general. Box 1, folder 1. 1964, n.d.. https://collections.library.yale.edu/catalog/16545905.

APA, 6th edition

Van Thal, Herbert, 1904-1983. (["Box 1, folder 1"])(1964, n.d.)["A" general]. https://collections.library.yale.edu/catalog/16545905.