MLA
Ritchie Bros. (Centralia, Ill.). Ben Brown and youngest son : Ben Brown wearing a suit, and his son wearing overalls, both sitting on chairs next to each other. unknown. Robert Langmuir African American Photograph Collection. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/552w3r22b8-cor.
APA, 6th edition
Ritchie Bros. (Centralia, Ill.). (unknown)[Ben Brown and youngest son : Ben Brown wearing a suit, and his son wearing overalls, both sitting on chairs next to each other]. Robert Langmuir African American Photograph Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/552w3r22b8-cor.
Chicago
Ritchie Bros. (Centralia, Ill.), Ben Brown and youngest son : Ben Brown wearing a suit, and his son wearing overalls, both sitting on chairs next to each other, unknown, Robert Langmuir African American Photograph Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/552w3r22b8-cor.