MLA

Warren, Robert Penn, 1905-1989. Introduction to Franklin Library edition: typescript and galley proofs (with letter). Box 98, folder 1820-21. 1977. https://collections.library.yale.edu/catalog/32194829.

APA, 6th edition

Warren, Robert Penn, 1905-1989. (["Box 98, folder 1820-21"])(1977)[Introduction to Franklin Library edition: typescript and galley proofs (with letter)]. https://collections.library.yale.edu/catalog/32194829.