U.S. Companies, Their Employees, and Violence in Colombia : Joint Hearing Before the Subcommittee on International Organizations, Human Rights, and Oversight and the Subcommittee on the Western Hemisphere of the Committee on Foreign Affairs, and the Subcommittee on Health, Employment, Labor, and Pensions and the Subcommittee on Workforce Protections of the Committee on Education and Labor, House of Representatives, One Hundred Tenth Congress, First Session, June 28, 2007