MLA

Clark, Warren Vester, 1821-1898. Warren Vester Clark, Sandusky, Ohio, to Wilson Hart Clark, New Haven, Connecticut. Box 1 | Folder 2. 1850 March 11. https://collections.library.yale.edu/catalog/17356864.

APA, 6th edition

Clark, Warren Vester, 1821-1898. (["Box 1 | Folder 2"])(1850 March 11)[Warren Vester Clark, Sandusky, Ohio, to Wilson Hart Clark, New Haven, Connecticut]. https://collections.library.yale.edu/catalog/17356864.