Flanagan, William G., 2010, Urban sociology: images and structure, 5th ed., Lanham: Rowman & Littlefield.
元データは、Adna F. Weber., 1899[1965], The Growth of Cities in the Nineteenth Century: A Study in Statistics, Ithaca, NY: Cornell University Press, 46, 60, 73, 84, 95, 101, 119, 120.）