00290pab a2200121 454500008004000000100002000040245003700060260000900097300001300106362000800119650001200127773002900139180718b2006   xxu||||| |||| 00| 0 eng d  aHunt, Robert M.  aWhen do more patents reduce R&D?  c2006  ap.87-91.  aMay  aPatents  aAmerican Economic Review