MLA
Robinson, R. L. Lewis Davis' Grandson, G.W. Davis, and Another African American Man Sitting and Standing next to a Machine on a Table. 1929. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 70. https://digital.library.emory.edu/purl/313zs7h47t-cor.
APA, 6th edition
Robinson, R. L. (1929). Lewis Davis' grandson, G.W. Davis, and another African American man sitting and standing next to a machine on a table (Box 70) [Photographic postcards]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/313zs7h47t-cor.
Chicago
Robinson, R. L. “Lewis Davis' Grandson, G.W. Davis, and Another African American Man Sitting and Standing next to a Machine on a Table.” Photographic postcards. Robert Langmuir African American Photograph Collection, 1929. Box 70. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/313zs7h47t-cor.