Cite

[No. 87: Photograph of two men with fallen horse]

MLA

[No. 87: Photograph of Two Men with Fallen Horse]. 1915. https://collections.library.yale.edu/catalog/11680511.

APA, 6th edition

[No. 87: Photograph of two men with fallen horse]. (1915). [Photographs, Slides (glass)]. https://collections.library.yale.edu/catalog/11680511.