MLA

Brown, Ella Barksdale, 1871-1966. Southern Sugar Company. Box 2, folder 86. undated. https://collections.library.yale.edu/catalog/31962052.

APA, 6th edition

Brown, Ella Barksdale, 1871-1966. (["Box 2, folder 86"])(undated)[Southern Sugar Company]. https://collections.library.yale.edu/catalog/31962052.