MLA
White. George W. Walker, Wearing a Coat and Holding a Hat above His Head. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 70. https://digital.library.emory.edu/purl/474cnp5htt-cor.
APA, 6th edition
W. George W. Walker, wearing a coat and holding a hat above his head (Box 70) [Postcards]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/474cnp5htt-cor.
Chicago
White. “George W. Walker, Wearing a Coat and Holding a Hat above His Head.” Postcards. Robert Langmuir African American Photograph Collection, n.d. Box 70. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/474cnp5htt-cor.