Columbia subject headings:
Harvard subject headings:
Communism--Europe--History--20th century
Communists--Europe--Biography.
New Left--History--20th century.
Right and left (Political science)
Socialism--Europe--20th century.
Socialism--History--20th century
Socialists--Europe--Biography.
Princeton subject headings:
Communism--Europe--History--20th century.
Communists--Europe--Biography.
Socialism--Europe--History--20th century.
Socialists--Europe--Biography.