MLA

Dellenbaugh, Frederick Samuel, 1853-1935. Wyoming. Box 2, folder 47. n.d.. https://collections.library.yale.edu/catalog/2017858.

APA, 6th edition

Dellenbaugh, Frederick Samuel, 1853-1935. (["Box 2, folder 47"])(n.d.)[Wyoming]. https://collections.library.yale.edu/catalog/2017858.