Employment of "green card" aliens during labor disputes [electronic resource] : hearings before the Special Subcommittee on Labor of the Committee on Education and Labor, House of Representatives, Ninety-first Congress, first session, on H.R. 12667 a bill to amend the National Labor Relations Act, as amended, so as to make it an unfair labor practice to employ aliens whose principal dwelling places are in a foreign country during a labor dispute, hearings held in Washington, D.C., July 16, 17; August 7, and 8, 1969.