?url_ver=Z39.88-2004&rft_id=10.3923%2Fjas.2011.1797.1802&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.aufirst=A.M.H.S.&rft.au=Lubis%2C+A.M.H.S.&rft.aulast=Lubis&rft.volume=11&rft.issn=18125654&rft.issue=10&rft.pages=1797-1802&rft.atitle=Investigation+of+worn+surface+characteristics+of+steel+influenced+by+jatropha+oil+as+lubricant+and+eco-friendly+lubricant+substituent&rft.title=Journal+of+Applied+Sciences&rft.date=2011&rft.genre=article