Zipf's Law for Cities: An Explanation
解释了为何多数国家的城市规模分布符合齐普夫定律，即大于某人口规模的城市数量与该规模成反比。若所有城市（至少是大型城市）遵循比例增长过程，其分布会自动收敛到齐普夫定律。
Zipf's law is a very tight constraint on the class of admissible models of local growth. It says that for most countries the size distribution of cities strikingly fits a power law: the number of cities with populations greater than <it>S</it> is proportional to 1/<it>S</it>. Suppose that, at least in the upper tail, all cities follow some proportional growth process (this appears to be verified emperically). This automatically leads their distribution to converge to Zipf's law.