Usage of natural gas [electronic resource] : hearing before the Committee on Energy and Natural Resources, United States Senate, One Hundred Twelfth Congress, second session, to assess the opportunities for, current level of investment in, and barriers to the expanded use of natural gas as a fuel for transportation, July 24, 2012.
Washington : U.S. G.P.O. : For sale by the Supt. of Docs., U.S. G.P.O., 2012.