Columbia subject headings:
Crusades.
Jihad--History.
War--Religious aspects--Christianity--History of doctrines.
War--Religious aspects--Islam--History of doctrines.
Harvard subject headings:
Crusades--History.
Jihad--History.
War--Religious aspects--Christianity--History of doctrines.
War--Religious aspects--Islam--History of doctrines.
Princeton subject headings:
Crusades.
Jihad.
War--Religious aspects--Christianity.
War--Religious aspects--Islam.