?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.aulast=Griffith&rft.au=Griffith%2C+R&rft.aufirst=R&rft.date=2004&rft.issue=4&rft.atitle=Mapping+the+two+faces+of+R%26D%3A+productivity+growth+in+a+panel+of+OECD+industries&rft.issn=0034-6535&rft.title=Review+of+Economics+and+Statistics&rft.pages=883-895&rft.volume=86&rft.genre=article