MLA
Alabama Post Card Co. (Bessemer, Ala.). Crystal Caverns Park : an African American man standing, and two African American sitting, on a ledge in Crystal Caverns Park. unknown. Robert Langmuir African American Photograph Collection. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/197xksn06q-cor.
APA, 6th edition
Alabama Post Card Co. (Bessemer, Ala.). (unknown)[Crystal Caverns Park : an African American man standing, and two African American sitting, on a ledge in Crystal Caverns Park]. Robert Langmuir African American Photograph Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/197xksn06q-cor.
Chicago
Alabama Post Card Co. (Bessemer, Ala.), Crystal Caverns Park : an African American man standing, and two African American sitting, on a ledge in Crystal Caverns Park, unknown, Robert Langmuir African American Photograph Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/197xksn06q-cor.