00623nam a2200169Ia 4500008004100000040001700041082002300058100002400081110004100105245004800146260003800194300000900232440006500241500001000306650011500316700002200431190327s9999||||xx |||||||||||||| ||und||  aNITILcNITIL  221sta338.09bE19O  aCornelli, Francesca  aEconomics of Industry Group (London) 0aOptimal patent renewalscFrancesca Cornelli  aLondonbSchool of Economicsc1996  a39p.  aThe economics of industry group: discussion paper series; 13  aEI/13  aIndustrialization-Great Britain; Industrial productivity; Patent laws and legislation; Economics-Great Britain  aSchankerman, Mark