MLA

Collier, J., and Charles. Harrington. Summering in Colorado. Richards & Co. (Denver : Press of Wm. N. Byers), 1874. https://collections.library.yale.edu/catalog/2019177.

APA, 6th edition

Collier, J., & Harrington, C. (1874). Summering in Colorado [Albumen prints, Photographic prints, Photographs]. Richards & Co. (Denver : Press of Wm. N. Byers). https://collections.library.yale.edu/catalog/2019177.