MLA
African American Boy Sitting on a Set of Stairs, with a Baby Girl Standing in Front of Him. 1903. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 28. https://digital.library.emory.edu/purl/668x95x6gg-cor.
APA, 6th edition
African American boy sitting on a set of stairs, with a baby girl standing in front of him (Box 28). (1903). [Card photographs (photographs)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/668x95x6gg-cor.
Chicago
“African American Boy Sitting on a Set of Stairs, with a Baby Girl Standing in Front of Him.” Card photographs (photographs). Robert Langmuir African American Photograph Collection, 1903. Box 28. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/668x95x6gg-cor.