MLA

Keller, Deane, 1901-1992. "Charley and the Captain" [notes for a history of Keller's and Charles Bernholz' service in WWII, unpublished]. Box 19, folder 1. undated. https://collections.library.yale.edu/catalog/10468086.

APA, 6th edition

Keller, Deane, 1901-1992. (["Box 19, folder 1"])(undated)["Charley and the Captain" [notes for a history of Keller's and Charles Bernholz' service in WWII, unpublished]]. https://collections.library.yale.edu/catalog/10468086.