Columbia subject headings:
Communism--History.
Communism.
Political science--History.
Political science.
Social history.
Socialism--History.
Socialism.
Harvard subject headings:
Communism--History
Communism.
Political science--History
Political science.
Social history.
Socialism--History
Socialism.
Princeton subject headings:
Communism--History.
Communism.
Political science--History.
Political science.
Social history.
Socialism--History.
Socialism.