Wonder drugs : hearings before the Subcommittee on Patents, Trademarks, and Copyrights, of the Committee on the Judiciary, United States Senate, Eighty-fourth Congress, second session, pursuant to S.Res.167, on licensing of United States government owned patents ; removal of obstacles to the production of essential materials from the cheapest source for the manufacture of cortisone and other hormones ; July 5-6, 1956