4FARE R. U.S. productivity in agriculture and R&D[J]. Joumal of Pro- ductivity Analysis ,2008,30( 1 ) :7- 12.
5BAIN C. The politics of food supply:P U.S. agricultural policy in the world economy[J]. Contemporary Sociology, 2010,39(2) : 212-213.
6BOTOLF P. The German information and communication technology (ICT) industry: spatial growth and innovation patterns [J]. Regional Studies ,2009,43(4) :605- 624.
7SERODIO c,CUNHA J B,MORAIS'*R. A networked platform for agricul- tural management systems[ J ]. Computers Electron Agdc ,2001,31 (1): 75-90.
8MIZUNUMA M, KATOH T, HATA S. Applying IT to farm fields:a wire- less LAN[J]. NTT Technical Review,2003,1 (2) :56-60.
