Cannan, Edwin (1927). "Why the Institution of Property is Maintained (A Letter to Dr. Scott Nearing, University of Pennsylvania, who had dedicated his book to "three men who grasp the real significance of the conflict between service and property income - Joseph E. Cohen, J. A. Hobson, Edwin Cannan" - July 18, 1915)". An Economist's Protest. London: P. S. King and Son, Ltd. pp. 35-42.