Fundamental issues in nonlinear urban population dynamic models: theory and a synthesis.

"The main purpose of this paper is to examine certain basic similarities between three nonlinear models of urban dynamics which appeared in [1980], and seem to be driven by somewhat different mechanisms.... By looking at their implicit assumptions we set the stage for addressing certain fundamental premises underlying the process of urban growth or decline. Searching for these fundamental assumptions permits the construction of a comprehensive-unifying theory of urban population dynamics placing urban evolution squarely within the domain of evolutionary theory."