MLA

Lindbergh, Anne Morrow, 1906-2001. Astor, Nancy. Box 2, folder 22. 1936-1955. https://collections.library.yale.edu/catalog/10016089.

APA, 6th edition

Lindbergh, Anne Morrow, 1906-2001. (["Box 2, folder 22"])(1936-1955)[Astor, Nancy]. https://collections.library.yale.edu/catalog/10016089.