MLA

Koch, Frederick R. (Frederick Robinson). Joubert, Joseph. Box 52, folder 1104. 1913 May 5. https://collections.library.yale.edu/catalog/2065835.

APA, 6th edition

Koch, Frederick R. (Frederick Robinson). (["Box 52, folder 1104"])(1913 May 5)[Joubert, Joseph]. https://collections.library.yale.edu/catalog/2065835.