Cite

[Photograph of Cavalry horses feeding at troughs]

MLA

[Photograph of Cavalry Horses Feeding at Troughs]. 0AD. https://collections.library.yale.edu/catalog/2017472.

APA, 6th edition

[Photograph of Cavalry horses feeding at troughs]. (0 C.E.). [Photographic postcards, Photographic prints, Photographs]. https://collections.library.yale.edu/catalog/2017472.