MLA

Marsh, Othniel Charles, 1831-1899. deErobriand, R.. Box 9, folder 418. 1873. https://collections.library.yale.edu/catalog/32556839.

APA, 6th edition

Marsh, Othniel Charles, 1831-1899. (["Box 9, folder 418"])(1873)[deErobriand, R.]. https://collections.library.yale.edu/catalog/32556839.