Columbia subject headings:
Harvard subject headings:
Atrocities--History--20th century--Congresses.
Military history, Modern--20th century--Congresses
Violence--Congresses
War--History--20th century--Congresses.
Princeton subject headings:
Atrocities--History--20th century--Congresses.
Military history, Modern--20th century--Congresses.
Violence--Congresses.
War--History--20th century--Congresses.