MLA

Lindbergh, Charles A. (Charles Augustus), 1902-1974. Transcontinental Air Transport route. Box 9, folder 3-8. 1929 July . https://collections.library.yale.edu/catalog/10080288.

APA, 6th edition

Lindbergh, Charles A. (Charles Augustus), 1902-1974. (["Box 9, folder 3-8"])(1929 July )[Transcontinental Air Transport route]. https://collections.library.yale.edu/catalog/10080288.