Actions for Mobil-Marathon and similar oil company mergers : hearing before the Subcommittee on Fossil and Synthetic Fuels of the Committee on Energy and Commerce, House of Representatives, Ninety-seventh Congress, first session on H.R. 4930, a bill to amend the Energy Policy and Conservation Act to provide for a comprehensive evaluation of the effects of acquisitions of domestic petroleum companies by major international energy concerns on the exploration, development, production, refining, transportation, distribution, and marketing of domestic petroleum supplies and to impose a moratorium on such acquisitions pending completion and consideration of the evaluation, December 10, 1981