MLA

Wharton, Edith, 1862-1937. Roosevelt, Theodore. Box 30, folder 919. 1915. https://collections.library.yale.edu/catalog/17111159.

APA, 6th edition

Wharton, Edith, 1862-1937. (["Box 30, folder 919"])(1915)[Roosevelt, Theodore]. https://collections.library.yale.edu/catalog/17111159.