1. Blair, William. 1833.An Inquiry Into the State of Slavery Amongst the Romans; From the Earliest Period, Till the Establishment of the Lombards in ItalyixEdinburgh
2. Cairnes, J. E. 1863.The Slave Power: Its Character, Career and Probable Designs: Being An Attempt to Explain the Real Issues Involved in the American Contest, 2nd ed. 109London and Cambridge
3. J. E. Cairnes on the Economics of American Negro Slavery