MLA
Rotograph Co. (New York, N.Y.). [Pickaninnies] : an African American girl sitting on stone steps. unknown. Robert Langmuir African American Photograph Collection. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/484mkkwh91-cor.
APA, 6th edition
Rotograph Co. (New York, N.Y.). (unknown)[[Pickaninnies] : an African American girl sitting on stone steps]. Robert Langmuir African American Photograph Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/484mkkwh91-cor.
Chicago
Rotograph Co. (New York, N.Y.), [Pickaninnies] : an African American girl sitting on stone steps, unknown, Robert Langmuir African American Photograph Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/484mkkwh91-cor.