MLA

Marsh, Othniel Charles, 1831-1899. Baring, Cecil. Box 2, folder 55. 1894. https://collections.library.yale.edu/catalog/32209078.

APA, 6th edition

Marsh, Othniel Charles, 1831-1899. (["Box 2, folder 55"])(1894)[Baring, Cecil]. https://collections.library.yale.edu/catalog/32209078.