MLA

Dellenbaugh, Frederick Samuel, 1853-1935. Yosemite. Box 2 | Folder 48. [1921]. https://collections.library.yale.edu/catalog/2017864.

APA, 6th edition

Dellenbaugh, Frederick Samuel, 1853-1935. (["Box 2 | Folder 48"])([1921])[Yosemite]. https://collections.library.yale.edu/catalog/2017864.