Columbia subject headings:
National security--United States.
Qaida (Organization)
Terrorism--Prevention.
War on Terrorism, 2001-
Harvard subject headings:
National security--United States
Qaida (Organization)
Terrorism--Prevention
War on Terrorism, 2001-2009
Princeton subject headings:
National security--United States.
Qaida (Organization)
Terrorism--Prevention.
War on Terrorism, 2001-2009.