MLA

Lindbergh, Charles A. (Charles Augustus), 1902-1974. In Russia. Box 16, folder 14. 1938 August 18-31. https://collections.library.yale.edu/catalog/10011519.

APA, 6th edition

Lindbergh, Charles A. (Charles Augustus), 1902-1974. (["Box 16, folder 14"])(1938 August 18-31)[In Russia]. https://collections.library.yale.edu/catalog/10011519.