7Bloom,N-, R. Griffith, R.,Van Reenen, J.. Do R&D TaxCredits Work. Evidence from a Panel of Countriesl979—1997[J]. Jour-nal of Public Economics, 2009, 85(1): 1—31.
8MaximEngers, Shannon K. Mitchell. R&D Policy with layersof economic integrationjj]. European Economic Review, 2005: 1791-1815.