MLA

Dellenbaugh, Frederick Samuel, 1853-1935. Glen Canyon. Box 4, folder 136. n.d.. https://collections.library.yale.edu/catalog/2025214.

APA, 6th edition

Dellenbaugh, Frederick Samuel, 1853-1935. (["Box 4, folder 136"])(n.d.)[Glen Canyon]. https://collections.library.yale.edu/catalog/2025214.