Columbia subject headings:
Harvard subject headings:
September 11 Terrorist Attacks, 2001--Congresses.
September 11 Terrorist Attacks, 2001--Political aspects--Congresses.
September 11 Terrorist Attacks, 2001--Religious aspects--Congresses.
Princeton subject headings:
September 11 Terrorist Attacks, 2001--Congresses.
September 11 Terrorist Attacks, 2001--Political aspects--Congresses.
September 11 Terrorist Attacks, 2001--Religious aspects--Congresses.