MLA

Whitney, Eli, 1765-1825. Correspondence, 1793. Box 1, folder 3, reel 1 | reel 1U. 1793. https://collections.library.yale.edu/catalog/10014140.

APA, 6th edition

Whitney, Eli, 1765-1825. (["Box 1, folder 3, reel 1 | reel 1U"])(1793)[Correspondence, 1793]. https://collections.library.yale.edu/catalog/10014140.