MLA

Keller, Deane, 1901-1992. Bernholz, Charles. Box 43, folder 61. 1914-1980. https://collections.library.yale.edu/catalog/10012682.

APA, 6th edition

Keller, Deane, 1901-1992. (["Box 43, folder 61"])(1914-1980)[Bernholz, Charles]. https://collections.library.yale.edu/catalog/10012682.