MLA
Groganphoto (Danville, Ill.). Charles Maxwell, guard, Lincoln's tomb, Springfield, Ill.. unknown. Robert Langmuir African American Photograph Collection. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/767wm37pxk-cor.
APA, 6th edition
Groganphoto (Danville, Ill.). (unknown)[Charles Maxwell, guard, Lincoln's tomb, Springfield, Ill.]. Robert Langmuir African American Photograph Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/767wm37pxk-cor.
Chicago
Groganphoto (Danville, Ill.), Charles Maxwell, guard, Lincoln's tomb, Springfield, Ill., unknown, Robert Langmuir African American Photograph Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/767wm37pxk-cor.