Cite

[Emil seated on a rock] on the ridge back of Paradise Valley. 106

MLA

[Emil Seated on a Rock] on the Ridge Back of Paradise Valley. 106. 0AD. https://collections.library.yale.edu/catalog/2015509.

APA, 6th edition

[Emil seated on a rock] on the ridge back of Paradise Valley. 106. (0 C.E.). [Photographic prints, Photographs, Stereographs]. https://collections.library.yale.edu/catalog/2015509.