MLA
Rotograph Co. (New York, N.Y.). Paul Laurence Dunbar, poet. unknown. Robert Langmuir African American Photograph Collection. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/020fttdz26-cor.
APA, 6th edition
Rotograph Co. (New York, N.Y.). (unknown)[Paul Laurence Dunbar, poet]. Robert Langmuir African American Photograph Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/020fttdz26-cor.
Chicago
Rotograph Co. (New York, N.Y.), Paul Laurence Dunbar, poet, unknown, Robert Langmuir African American Photograph Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/020fttdz26-cor.