MLA

Dellenbaugh, Frederick Samuel, 1853-1935. Unidentified. Box 3, folder 80. ca. 1878. https://collections.library.yale.edu/catalog/2018221.

APA, 6th edition

Dellenbaugh, Frederick Samuel, 1853-1935. (["Box 3, folder 80"])(ca. 1878)[Unidentified]. https://collections.library.yale.edu/catalog/2018221.