1. Cesare Lombroso, “La physionomie des anarchistes,” Nouvelle Revue, May 15, 1891, 225–230.
2. Wilbur R. Miller, Cops and Bobbies: Police Authority in New York and London, 1830–1870 (Chicago: University of Chicago Press, 1977), 142.
3. Robert A. Nye, The Origins of Crowd Psychology: Gustave Le Bon and the Crisis of Mass Democracy in the Third Republic (Beverly Hills, CA: Sage, 1975), 22
4. Daniel Pick, Faces of Degeneration: A European Disorder, c.1848-c.1918 (New York: Cambridge University Press, 1989), 71.
5. Allan Pinkerton, Strikers, Communists, Tramps, and Detectives (New York: G. W. Carleton, 1900), 229–230.