MLA

Lindbergh, Charles A. (Charles Augustus), 1902-1974. New Haven speech. Box 202, folder 358-359. 1940 October 30. https://collections.library.yale.edu/catalog/10013898.

APA, 6th edition

Lindbergh, Charles A. (Charles Augustus), 1902-1974. (["Box 202, folder 358-359"])(1940 October 30)[New Haven speech]. https://collections.library.yale.edu/catalog/10013898.