↑Ellickson، Robert (1994). Order without Law: How Neighbors Settle Disputes.
↑Dickinson, Robert E. (1961) The West European City: A Geographical Interpretation. Routledge & Paul, London, p. 529. See also: Jacobs, Jane (1961) The Death and Life of Great American Cities. Random House, New York, p. 117.
↑Schuck, Amie and Dennis Rosenbuam 2006 "Promoting Safe and Healthy Neighborhoods: What Research Tells Us about Intervention." The Aspen Institute.