1. Aeromapas Seravenca, C. A. (Venezuela).Mapa de Carreteras de Venezuela, Edicion 1971. Caracas: Creole Petroleum Corp., 1971.
2. A. I. D., Bureau for Latin American Rural Development.Atlas No. 8: Venezuela, Washington, D. C.: Dept. of the Army, Engineering Agency for Resources Inventory, 1968.
3. Artle, Roland. ?Urbanization and Economic Growth in Venezuela,?Papers and Proceedings of the Regional Science Association, 27 (1970?71): 63?93.
4. Banco Nacional de Ahorro Y Prestamo (Venezuela).Estudio del Mercado Real de Vivienda en Venezuela: 1970, Caracas: 1973.
5. Beals, R. E., M. B. Levy, and L. N. Moses. ?Rationality and Migration in Ghana,?Review of Economics and Statistics, 49 (1967): 480?486.