MLA

Dimon, Charles Augustus Ropes, 1841-1902. Correspondence. Box 1, folder 17-18. 1864 Aug. https://collections.library.yale.edu/catalog/17200082.

APA, 6th edition

Dimon, Charles Augustus Ropes, 1841-1902. (["Box 1, folder 17-18"])(1864 Aug)[Correspondence]. https://collections.library.yale.edu/catalog/17200082.