Patent law revision, hearings before Subcommittee on Patents, Trademarks, and Copyrights, 90th Congress, 2d session, pursuant to S. Res. 37 on S. 2, S. 1042, S. 1377, S. 1691, S. 2164, S. 2597. pt. 2. Jan. 30-Feb. 1, 1968.