MLA

Lindbergh, Charles A. (Charles Augustus), 1902-1974. Grumman Aerospace Corporation dinner. Box 19, folder 14. 1969 July 15. https://collections.library.yale.edu/catalog/10013335.

APA, 6th edition

Lindbergh, Charles A. (Charles Augustus), 1902-1974. (["Box 19, folder 14"])(1969 July 15)[Grumman Aerospace Corporation dinner]. https://collections.library.yale.edu/catalog/10013335.