Racing to Zipf's law: Race and metropolitan population size 1910–2020
研究了1910至2020年美国大都市区白人和黑人人口规模分布，发现白人分布基本符合齐普夫定律，而黑人直到20世纪下半叶才符合，这与吉姆·克劳时代黑人流动性受限的理论一致。
Abstract Scholarship demonstrates that urban systems follow a power law population distribution if the population has full labor mobility. Theoretically, subpopulations should also follow a power law population distribution if that subpopulation also has full labor mobility. Examining city population distributions for White and Black Americans across US metropolitan areas from 1910 to 2020 shows that the White distribution mostly conforms to both Zipf's and Gibrat's laws throughout this period. In contrast, the Black population does not follow either law until the second half of the 20th century, a result that is consistent with theories of restricted mobility out of the South for Black Americans during the Jim Crow era.