3Bourdieu P. The forms of capital. In J. Richardson( Ed. ) Handbook of Theory and Research for the Sociology of Education, New York, Green- wood, 1986:241 - 258.
4Burr R S. Structural Holes:The Social Structure of Competition. Cambridge:Harvard University Press, 1992.
5Grmaovetter M. The Strength of Weak Tie. American Journal of Sociology, 1973,78 (6) :1360 - 1380.
6Granovetter M. Economic Action and Social Structure :the Problem of Embeddedness. American Journal of Sociology, 1985,91 (3) :481 -510.
7Rutten R, Boekema F. Regional social capital : Embeddedness, innovation networks and regional economic development. Technological Forecas- ting and Social Change,2007,74 (9) : 1834 - 1846.