title: Urban ecology:  urbanization and systems of cities.
abstract: "This paper reviews the literature on the nature and extent of interrelations among cities in advanced industrial societies.  It summarizes contemporary population distribution and redistribution trends in these societies and their causes.  Finally, it attempts to identify some of the most important issues for the development of a comparative theory of urbanization."
mesh_terms: D003710:Demography; D019049:Developed Countries; D005843:Geography; D011153:Population; D011154:Population Characteristics; D011157:Population Dynamics; D014505:Urban Population; D014507:Urbanization
keywords: Demographic Factors; Developed Countries; Geographic Factors; Literature Review; Population; Population Characteristics; Population Theory; Spatial Distribution; Urban Population; Urban Spatial Distribution; Urbanization