MLA
Four Men in Suits, One African American Man : with Two Standing and Two Sitting. 1909. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 72. https://digital.library.emory.edu/purl/750tqjq2dx-cor.
APA, 6th edition
Four men in suits, one African American man : with two standing and two sitting (Box 72). (1909). [Postcards]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/750tqjq2dx-cor.
Chicago
“Four Men in Suits, One African American Man : with Two Standing and Two Sitting.” Postcards. Robert Langmuir African American Photograph Collection, 1909. Box 72. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/750tqjq2dx-cor.