8North, D. C. , Understanding the Process of Economic Change, NJ: Princeton University Press, 2005.
9ASCHAUER D A. Is public expenditure productive?[J]. Journal of Monetary Economics, 1989(23):177-200.
10RENKOW M, HALLSTROM D, KARANJA D. Rural infras turcture, transactions costs and market participation in Kenya [J]. Journal of Development Economics, 2003, 73 ( 1 ) : 349- 367.