MLA

Willis, John, 1957-. American Indian Movement, Water Protectors. Box 2 (Oversize), folder 3. undated. https://collections.library.yale.edu/catalog/32576142.

APA, 6th edition

Willis, John, 1957-. (["Box 2 (Oversize), folder 3"])(undated)[American Indian Movement, Water Protectors]. https://collections.library.yale.edu/catalog/32576142.