MLA
Advertising, Standard, and Ptg. Gus Allen's Hotel, with Portraits of Gus Allen, Sr., Owner and Gus Allen, Jr., Manager. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 71. https://digital.library.emory.edu/purl/38279cnp6z-cor.
APA, 6th edition
Advertising, S., & P. Gus Allen's Hotel, with portraits of Gus Allen, Sr., Owner and Gus Allen, Jr., Manager (Box 71) [Postcards]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/38279cnp6z-cor.
Chicago
Advertising, Standard, and Ptg. “Gus Allen's Hotel, with Portraits of Gus Allen, Sr., Owner and Gus Allen, Jr., Manager.” Postcards. Robert Langmuir African American Photograph Collection, n.d. Box 71. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/38279cnp6z-cor.