MLA

Stewart, Donald Ogden, 1894-1980. Unsorted correspondence, includes some correspondence, notes, photos, newspaper clippings, printed ephemera. Box 7. undated. https://collections.library.yale.edu/catalog/16867644.

APA, 6th edition

Stewart, Donald Ogden, 1894-1980. (["Box 7"])(undated)[Unsorted correspondence, includes some correspondence, notes, photos, newspaper clippings, printed ephemera]. https://collections.library.yale.edu/catalog/16867644.