Columbia subject headings:
Emergency management--United States.
National security--United States.
Natural disasters--United States--Planning.
Terrorism--Prevention--Government policy--United States.
Harvard subject headings:
Emergency management--United States
National security--United States
Natural disasters--United States--Planning.
Terrorism--Prevention--Government policy--United States
Princeton subject headings:
Emergency management--United States.
National security--United States.
Natural disasters--United States--Planning.
Terrorism--Prevention--Government policy--United States.