MLA
Hugh C. Leighton Co., Manufacturers (Portland, Me.). Newport, R.I., Negro Head, south of Purgatory. unknown. Robert Langmuir African American Photograph Collection. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/320sqv9s6j-cor.
APA, 6th edition
Hugh C. Leighton Co., Manufacturers (Portland, Me.). (unknown)[Newport, R.I., Negro Head, south of Purgatory]. Robert Langmuir African American Photograph Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/320sqv9s6j-cor.
Chicago
Hugh C. Leighton Co., Manufacturers (Portland, Me.), Newport, R.I., Negro Head, south of Purgatory, unknown, Robert Langmuir African American Photograph Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/320sqv9s6j-cor.