MLA

Percival, James Gates, 1795-1856. Correspondence. Box 18, folder 435. 1859-1866. https://collections.library.yale.edu/catalog/17067796.

APA, 6th edition

Percival, James Gates, 1795-1856. (["Box 18, folder 435"])(1859-1866)[Correspondence]. https://collections.library.yale.edu/catalog/17067796.