MLA
Porch, Harvey W. Men Standing in Front of a Railroad Train. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 55. https://digital.library.emory.edu/purl/624jm63xz1-cor.
APA, 6th edition
Porch, H. W. Men standing in front of a railroad train (Box 55) [Card photographs (photographs)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/624jm63xz1-cor.
Chicago
Porch, Harvey W. “Men Standing in Front of a Railroad Train.” Card photographs (photographs). Robert Langmuir African American Photograph Collection, n.d. Box 55. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/624jm63xz1-cor.