Columbia subject headings:
Crimes against humanity--History--20th century.
Crimes against humanity.
Genocide--History--20th century.
Genocide--Sociological aspects.
Political atrocities--History--20th century.
State-sponsored terrorism--History--20th century.
State-sponsored terrorism.
Harvard subject headings:
Crimes against humanity.
Genocide--History--20th century.
Genocide--Sociological aspects
Political atrocities--History--20th century.
Princeton subject headings:
Crimes against humanity.
Genocide--History--20th century.
Genocide--Sociological aspects.
Political atrocities--History--20th century.