MLA

Lindbergh, Charles A. (Charles Augustus), 1902-1974. Airline Pilot Association meeting. Box 19, folder 8. 1969 . https://collections.library.yale.edu/catalog/10011515.

APA, 6th edition

Lindbergh, Charles A. (Charles Augustus), 1902-1974. (["Box 19, folder 8"])(1969 )[Airline Pilot Association meeting]. https://collections.library.yale.edu/catalog/10011515.