MLA

Ford, Julia Ellsworth, 1859-1950. Augell, Norman. Box 1, folder 3. 1917-1919, undated. https://collections.library.yale.edu/catalog/17167800.

APA, 6th edition

Ford, Julia Ellsworth, 1859-1950. (["Box 1, folder 3"])(1917-1919, undated)[Augell, Norman]. https://collections.library.yale.edu/catalog/17167800.