Cite

Naco, Sonora, federal soldiers at rest stacked arms

MLA

Undritz, F. R. Naco, Sonora, Federal Soldiers at Rest Stacked Arms. 0AD. https://collections.library.yale.edu/catalog/2015416.

APA, 6th edition

Undritz, F. R. (0 C.E.). Naco, Sonora, federal soldiers at rest stacked arms [Photographic postcards, Photographic prints, Photographs]. https://collections.library.yale.edu/catalog/2015416.