1. Distribution of the World's City Folks: A Study in Comparative Civilization
2. The Law of the Primate City
3. Clyde, E. Browning discusses the “optimum city size” by consideration of the “urban system.” in “Primate Cities and Related Concepts,”. Urban Systems and Economic Development, Conference on Urban Systems research in Underdeveloped and Advanced Economies. Edited by: Forrest, R and Eugene, Pitts. pp.16–27. Oregon: School of Business Administration, University of Oregon).