1. A. Blank, S. Solomon, Power law and cities population, Published on line (2000) URL: http://xxx.tau.ac.il/html/cond-mat/0003240.
2. On a class of skew distribution functions;Simon;Biometrika,1955
3. Human Behavior and the Principle of Least Effort;Zipf,1949
4. Regions and International Trade;Fujita,1999
5. An Essay on Urban Economic Theory;Papageorgiou,1999