3Alperovich G. 1992, Economic Development and Population Concentration, Economic Development and Cultural Change, 41, pp. 63-74.
4Ottaviano G I P, Puga D, 1998, Agglomeration in the Global Economy. A Survey of the New Economic Geography, World Economy,Vol. 21, Issue 6, pp 707-731.
5Paluzie E, Pore J, and Tirado D A. 2001, Regional Integration and Specialization Patterns in Spain, Regional Studies. Vol 35. 4pp. 285-296.
6Puga D. 1999, The Rise and Fall of Regional Inequality, European Economic Review, No 43, pp 303-334.
7Kurgman P, 1991, Increasing Returns and Economic Geography,Journal of Political Economy, Vol 9, no 3, pp 483-499.
8Terrasi M. 1999, Convergence and Divergence across Italian Region, The Annals of Regional Science, 33 (3), pp 486-510.
9Williamson J G. 1965, Regional Inequality and the Process of National Development. A Description of the Patterns, Economic Development and Cultural Change, Vol 13, no 4, pp 3-45.