Cite

[Photograph of pack horses]

MLA

Dellenbaugh, Frederick Samuel, 1853-1935. [Photograph of pack horses]. Box 2 | Folder 39. undated. https://collections.library.yale.edu/catalog/2017806.

APA, 6th edition

Dellenbaugh, Frederick Samuel, 1853-1935. (["Box 2 | Folder 39"])(undated)[[Photograph of pack horses]]. https://collections.library.yale.edu/catalog/2017806.