6Griliches,Z.1992 The search for R&D spillovers,Scandinavian Journal of Economics 94:29-47.
7Verspagen,B.1997 Estimating international technology spillovers using technology flow matrices,Weltwirtschaftliches Archives 133:226-324.
8Jaffe,A.,Trajtenberg,M.and Henderson,R.1993Geographic localization of knowledge spillovers as evidenced by patent citations,Quarterly Journal of Economics 108:577-598.
9Angel,D.1989 The labor market fox engineers in the US semi-conductor industry,Economic Geography 65 (2):99-112.
10Tallman,S.,Jenkins,M.,Henry,N.and Pinch,S.1999Knowledge clusters and competitive advantage in global industries,Working paper presented in Strategic Management Society 1999 Conference.