1. ALONSO, W. (1980): Populatin as a System in Regional Development. Paper and Proceedings of Amer. Eco. Rev., 70, 405-409.
2. BROWN, L. A. AND J. P. JoNEs III (1985): Spatial Variation in Migration Processes and Development: A Costa Rican Example of Conventional Modeling Augmented by the Expansion Model. Demography, 22, 327-352.
3. BUTZ, W. P. AND M. P. WARD (1979): The Emergence of Countercyclical U. S. Fertility. The Amer. Eco. Rev., 69, 318-328.
4. CASETTI, E. (1972): Generating Models by the Expansion Method: Applications to Geographic Research. Geographical Analysis, 4, 81-91.
5. CASETTI, E. (1982): Mathematical Modeling and the Expansion Method. in R. B. MANDEL (ed.) Statistics for Geographers and Social Scientists, Cencept Publishing Company, New Delhi, India 81-95.