Premerger notification : hearings before the Antitrust Subcommittee (Subcommittee No. 5) of the Committee on the Judiciary, House of Representatives, Eighty-fifth Congress, first session on H.R. 264 and H.R. 2143, bills to amend the Clayton Act, as amended, by requiring prior notification of corporate mergers and acquisitions, and for other purposes, March 6, 7, 8, 20, and 21, 1957