MLA

Mason, William Smith, 1866-. Kenneth Morrison papers. Box 61 (Oversize), folder 2273. 1762–1783. https://collections.library.yale.edu/catalog/33490158.

APA, 6th edition

Mason, William Smith, 1866-. (["Box 61 (Oversize), folder 2273"])(1762–1783)[Kenneth Morrison papers]. https://collections.library.yale.edu/catalog/33490158.