MLA

Dunbar, Rudolph, 1899-1988. "J" general. Box 1, folder 18. 1942–1971. https://collections.library.yale.edu/catalog/17398733.

APA, 6th edition

Dunbar, Rudolph, 1899-1988. (["Box 1, folder 18"])(1942–1971)["J" general]. https://collections.library.yale.edu/catalog/17398733.