The study of Plan Colombia an assessment of successes and challenges : hearing before the Subcommittee on Criminal Justice, Drug Policy, and Human Resources of the Committee on Government Reform, House of Representatives, One Hundred Seventh Congress, first session, March 2, 2001.

Antzeko izenburuak

• The crisis in Colombia what are we facing? : hearing before the Subcommittee on Criminal Justice, Drug Policy, and Human Resources of the Committee on Government Reform, House of Representatives, One Hundred Sixth Congress, second session, February 15, 2000.
  Argitaratua: (2000)
• U.S. policy regarding narcotics control in Colombia hearing before the Caucus on International Narcotics Control, United States Senate, One Hundred Eighth Congress, first session, June 3, 2003.
  Argitaratua: (2004)
• The narcotics threat from Colombia hearing before the Subcommittee on Criminal Justice, Drug Policy, and Human Resources of the Committee on Government Reform, House of Representatives, One Hundred Sixth Congress, first session, August 6, 1999.
  Argitaratua: (2001)
• Plan Colombia the strategic and operational imperatives /
  nork: Marcella, Gabriel.
  Argitaratua: (2001)
• Plan Colombia major successes and new challenges : hearing before the Committee on International Relations, House of Representatives, One Hundred Ninth Congress, first session, May 11, 2005.
  Argitaratua: (2005)