MLA

Lindbergh, Anne Morrow, 1906-2001. Dulles, John Foster. Box 7, folder 123. 1940-1955. https://collections.library.yale.edu/catalog/10016107.

APA, 6th edition

Lindbergh, Anne Morrow, 1906-2001. (["Box 7, folder 123"])(1940-1955)[Dulles, John Foster]. https://collections.library.yale.edu/catalog/10016107.