MLA
Obermuller & Son (N.Y.). African American man in a top hat and a hand on a chair. unknown. Robert Langmuir African American Photograph Collection. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/750tqjq2fk-cor.
APA, 6th edition
Obermuller & Son (N.Y.). (unknown)[African American man in a top hat and a hand on a chair]. Robert Langmuir African American Photograph Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/750tqjq2fk-cor.
Chicago
Obermuller & Son (N.Y.), African American man in a top hat and a hand on a chair, unknown, Robert Langmuir African American Photograph Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/750tqjq2fk-cor.