Cite

[Photograph of a Cavalry officer and his horse]

MLA

[Photograph of a Cavalry Officer and His Horse]. 0AD. https://collections.library.yale.edu/catalog/2017422.

APA, 6th edition

[Photograph of a Cavalry officer and his horse]. (0 C.E.). [Photographic postcards, Photographic prints, Photographs]. https://collections.library.yale.edu/catalog/2017422.