4CLARK C. The conditions of economic progress [ M ] London : 1 st Edition, Macmillan, 1940:685 -691.
5CASTELLS. The information age : Economy, society, and culture. Vol. 1. [M]. New Jersey: Blackwell, 1996:391-395.
6MARKUSEN. Trade in producer services and in other specialized in- termediate inputs [ J]. Economic Review. 1989, 79 (1): 85 - 89.
7BURGESS D F. Is trade liberalization in the service sector in the na- tional interest [J]. Oxford Economic Paper, 1995 (47) : 60 -78.
8FEENSTRA R C, HANSON G H. The Impact of Outsourcing and High -Technology Capital on Wages: Estimates for the United States, 1979 -1990 [J]. The Quarterly Journal of Economics. 1999, 114 ( 3 ) : 907 - 940.
9ESWARAN K. Theory of the service section in the process of indus- trialization [ J ]. Journal of Development Economics, 2002 (68) : 401 - 420.
10FRANCOIS J, WOERZ J. Producer services, manufacturing linka- ges, and trade [ J ]. Journal of Industry, Competition and Trade, 2008 (8): 199-229.