MLA

Huntington, Ellsworth, 1876-1947. D. Box 1, folder 5. 1947, undated. https://collections.library.yale.edu/catalog/32507049.

APA, 6th edition

Huntington, Ellsworth, 1876-1947. (["Box 1, folder 5"])(1947, undated)[D]. https://collections.library.yale.edu/catalog/32507049.