MLA
Artvue Post Card Co. (New York, N.Y.). The door to Christian service, Dayton Bible Institute, Dayton, Ohio. unknown. Robert Langmuir African American Photograph Collection. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/7375tb2rff-cor.
APA, 6th edition
Artvue Post Card Co. (New York, N.Y.). (unknown)[The door to Christian service, Dayton Bible Institute, Dayton, Ohio]. Robert Langmuir African American Photograph Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/7375tb2rff-cor.
Chicago
Artvue Post Card Co. (New York, N.Y.), The door to Christian service, Dayton Bible Institute, Dayton, Ohio, unknown, Robert Langmuir African American Photograph Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/7375tb2rff-cor.