MLA
United States Army, Four Armed Soldiers in the Field on Mexican Border, Ca. 1916-1917. 1916. Stuart A. Rose Manuscript, Archives, and Rare Book Library, OP74. https://digital.library.emory.edu/purl/12683bk3kn-cor.
APA, 6th edition
United States Army, Four armed soldiers in the field on Mexican border, ca. 1916-1917 (OP74). (1916). [Card photographs (photographs)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/12683bk3kn-cor.
Chicago
“United States Army, Four Armed Soldiers in the Field on Mexican Border, Ca. 1916-1917.” Card photographs (photographs). Robert Langmuir African American Photograph Collection, 1916. OP74. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/12683bk3kn-cor.