MLA
Riddell, J. H., Mrs., 1832-1906. The earl's promise [1878]. 1878. Chester W. Topp collection of Victorian yellowbacks and paperbacks. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/69673n5txp-cor.
APA, 6th edition
Riddell, J. H., Mrs., 1832-1906. (1878)[The earl's promise [1878], New edition.]. Chester W. Topp collection of Victorian yellowbacks and paperbacks, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/69673n5txp-cor.
Chicago
Riddell, J. H., Mrs., 1832-1906, The earl's promise [1878], 1878, Chester W. Topp collection of Victorian yellowbacks and paperbacks, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/69673n5txp-cor.