1Shiferaw Gurmu.Fidel Pérez-Sebastián.“Patents,R&Dand Lag Effects:Evidence from Flexible Methods for CountPanel Data on Manufacturing Firms”.Empirical Economics[J].2008,35(3):507-526.
2Maria JoséGil-Moltó,Joanna Poyago-Theotoky and Va-sileios Zikos.“R&D Subsidies,Spillovers,and Privatiza-tion in Mixed Markets”.Southern Economic Journal[J].2011,78(1):233-255.
3Birgit Aschhoff.“Who Gets the Money?The Dynamics ofR&D Project Subsidies in Germany”.Jahrbucher fur Na-tionalokonomie und Statistik[J].2010,230(5):522-546.