1Webber M.M. The urban place and nonplace urban realm[M] .in Webber M.M. et al. (eds.)Exploration into Urban Structure, University of Pennsylvania Press, Philadelphia,1964.
2W. J. Reilly, Methods for the Study of Retail Relationship[J]. University of Texas, Bureau of Business Research., Research Monograph(University of Texas Bulletin No. 2994), November 1929, (4).
3W.Isard. Methods of Regional Analysis: An Introduction to Regional Science[M]. New York, London, John Wiley&Sons, 1960.
4S. C. Dodd, The Interactance Hypothesis: A Gravity Model Fitting Physical Masses snd Human Groups[M]. American Sociological Review, April 1950.245- 256.
5W.G. Hansen, Evaluation of Gravity Model Trip Distribution Procedures[M].Highway Research Board Bulletin 347, 1962.67-76.
6J.J. Pipan, Gravity Model Procedures Used by Iowa Planning Survey[M]. U.S. Bureau of Public Roads, Region 5, Kansas City, Mo.,1962.
7Richard J. Bouchard and Clyde E. Pyers, The Use of Gravity Model for Forecasting Urban Travel - An Analysis and Critique[ M]. presented at the 43rd annual meeting of the Highway Research Board, January 1964.
