MLA

Dellenbaugh, Frederick Samuel, 1853-1935. Florida. Box 2, folder 56. n.d.. https://collections.library.yale.edu/catalog/2017890.

APA, 6th edition

Dellenbaugh, Frederick Samuel, 1853-1935. (["Box 2, folder 56"])(n.d.)[Florida]. https://collections.library.yale.edu/catalog/2017890.