MLA

Van Thal, Herbert, 1904-1983. "D" general. Box 1, folder 29. 1949. https://collections.library.yale.edu/catalog/16545933.

APA, 6th edition

Van Thal, Herbert, 1904-1983. (["Box 1, folder 29"])(1949)["D" general]. https://collections.library.yale.edu/catalog/16545933.