Group bargaining by milk cooperatives : hearings before the Antitrust Subcommittee (Subcommittee no. 5) of the Committee on the Judiciary, House of Representatives, Eighty-sixth Congress, first session, on S. 753 and H.R. 7191, bills to authorize cooperative associations of milk producers to bargain with purchasers singly or in groups, and for other purposes, August 20-21, 1959.