1[1]C.Freeman:The aeaconomics of Industrial Innovation The MIT Press,1982,pp.34.
2[5]W.Baldwin and J.Scott:Market Structure and Technolofical Change,Switzerland:Harwood Academic publishers,1987,pp.76-85.
3[6]F.Scherer:"Research and Development Resource Allocation under Rivalry"in F.Scherer:Innovation and Growth,CambridgeMass:The MIT Press,1984,pp.83-119.
4[8]Etiemme Barral:20years of pharmceutical research,Market Letter,1996,23:12.