MLA

Lindbergh, Charles A. (Charles Augustus), 1902-1974. North Atlantic survey flight, place unspecified. Box 12, folder 7-12. Circa 1933 July 20-August 6. https://collections.library.yale.edu/catalog/10013265.

APA, 6th edition

Lindbergh, Charles A. (Charles Augustus), 1902-1974. (["Box 12, folder 7-12"])(Circa 1933 July 20-August 6)[North Atlantic survey flight, place unspecified]. https://collections.library.yale.edu/catalog/10013265.