"epa-420-r-99-023" . "Regulatory Impact Analysis - Control of Air Pollution from New Motor Vehicles: Tier 2 Motor Vehicle Emissions Standards and Gasoline Sulfur Control Requirements"^^ . "1999"^^ . "http://www.epa.gov/tier2/documents/r99023.pdf"^^ . "report" . . . . . . . _:genid1 . _:genid1 . _:genid1 . _:genid1 . _:genid2 . _:genid2 . _:genid2 . _:genid2 .