MLA

Van Thal, Herbert, 1904-1983. Foyle, Christina. Box 1, folder 43. 1965 Feb 2. https://collections.library.yale.edu/catalog/16545947.

APA, 6th edition

Van Thal, Herbert, 1904-1983. (["Box 1, folder 43"])(1965 Feb 2)[Foyle, Christina]. https://collections.library.yale.edu/catalog/16545947.