Cite

[No. 10: Photograph of two men loading pack horse]

MLA

[No. 10: Photograph of Two Men Loading Pack Horse]. 1915. https://collections.library.yale.edu/catalog/11679500.

APA, 6th edition

[No. 10: Photograph of two men loading pack horse]. (1915). [Photographs, Slides (glass)]. https://collections.library.yale.edu/catalog/11679500.