MLA

Marsh, Othniel Charles, 1831-1899. Brown, Frederick. Box 5, folder 168. 1888 July - 1889 June. https://collections.library.yale.edu/catalog/32554207.

APA, 6th edition

Marsh, Othniel Charles, 1831-1899. (["Box 5, folder 168"])(1888 July - 1889 June)[Brown, Frederick]. https://collections.library.yale.edu/catalog/32554207.