MLA

Little Raven. Principal Araphoe Chief. William Soule, 0AD. https://collections.library.yale.edu/catalog/2010367.

APA, 6th edition

Little Raven. Principal Araphoe Chief. (0 C.E.). [Photographic prints, Photographs, Studio portraits]. William Soule. https://collections.library.yale.edu/catalog/2010367.