MLA
Mora, O. de la. Nobody Knows : Three Men Wearing Suits and Top Hats, Carrying Canes Standing with an Arm Resting on a Tree Stump or a Rock with an African American Man Wearing a Suit and Top Hat Seated at Their Feet Holding a Rifle. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 63. https://digital.library.emory.edu/purl/177fqz614p-cor.
APA, 6th edition
Mora, O. de la. Nobody knows : three men wearing suits and top hats, carrying canes standing with an arm resting on a tree stump or a rock with an African American man wearing a suit and top hat seated at their feet holding a rifle (Box 63) [Card photographs (photographs)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/177fqz614p-cor.
Chicago
Mora, O. de la. “Nobody Knows : Three Men Wearing Suits and Top Hats, Carrying Canes Standing with an Arm Resting on a Tree Stump or a Rock with an African American Man Wearing a Suit and Top Hat Seated at Their Feet Holding a Rifle.” Card photographs (photographs). Robert Langmuir African American Photograph Collection, n.d. Box 63. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/177fqz614p-cor.