American Gas Association http://www.aga.org/ California Energy Commission http://www.energy.ca.gov/ Canadian Gas Association http://www.cga.ca/ Canadian Natural Gas Vehicle Alliance http://www.ngvcanada.org/ CSA International http://www.csa-international.org/ Clean Cities http://www.eere.energy.gov/cleancities Honda GX http://www.civicgx.com International Association for Natural Gas Vehicles http://www.iangv.org/ Natural Gas Vehicle Coalition http://www.ngvc.org/ U.S. Alternative Fuels Data Centre http://www.eere.energy.gov/afdc U.S. Department of Energy http://www.doe.gov/ U.S. Energy Information Natural Gas Administration http://www.eia.doe.gov/oil_gas/natural_gas/nat_frame.html U.S EPA Fuel Economy Site www.fueleconomy.gov