1The World Bank. World Development Report 2009:Re- shaping Economic Geography[R].World Bank, 2008.
2Ciccone Antonio,Hall Robert E. Productivity and the density of economic activity[J].American Economic Re- view, 1996.86.1.
3Ciccone Antonio. Agglomeration effects in Europe [J].European Economic Review, 2002.46.2.
4Marius Brfilhart,Nicole A Mathys. Sectoral agglom- eration economies in a panel of European regions[J]. Regional Science and Urban Economics,2008.38.4.