Juvenile delinquency, hearing before Subcommittee to Investigate Juvenile Delinquency, 89th Congress, 2d session, 90th Congress, 1st session, pursuant to S. Res. 199, 89th Congress, S. Res. 35, 90th Congress, pt. 17. Youth, obscene materials, and United States mails, Dec. 16, 1966 and Feb. 9, 1967.