MLA
Artvue Post Card Co. (New York, N.Y.). African American boys and young men playing football, with a line of people watching from the sideline, at Camp Atwater, in East Brookfield, Massachusetts. unknown. Robert Langmuir African American Photograph Collection. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/6623bk3jf2-cor.
APA, 6th edition
Artvue Post Card Co. (New York, N.Y.). (unknown)[African American boys and young men playing football, with a line of people watching from the sideline, at Camp Atwater, in East Brookfield, Massachusetts]. Robert Langmuir African American Photograph Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/6623bk3jf2-cor.
Chicago
Artvue Post Card Co. (New York, N.Y.), African American boys and young men playing football, with a line of people watching from the sideline, at Camp Atwater, in East Brookfield, Massachusetts, unknown, Robert Langmuir African American Photograph Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/6623bk3jf2-cor.