1. Burghardt A F, 1971. A hypothesis about gateway cities.Annals of the Association of American Geographers, 61: 269–285.
2. Boventer E V, 1979. Standortentscheidung und Raumstruktur. Hannover.
3. Chen Jiyu, 1979. The develop mode of Yangtze bayou in two thousand years.Acta Oceanologica Sinica, 1(1): 103–111. (in Chinese)
4. Christaller W (translated by Baskin C W), 1966. Central Places in Southern Germany. Englewood Cliffs, NL: Prentice Hall, 63.
5. Dong Ping, 2000. Due-nuclei spatial structure and regional development in France.World Regional Studies, (4): 65–68. (in Chinese)