Columbia subject headings:
Harvard subject headings:
Communism--History--20th century
Nineteen sixty-eight, A.D.
Protest movements--History--20th century.
Social movements--Germany--History--20th century.
Social movements--History--20th century.
Socialism--Germany--History--20th century
Socialism--History--20th century
Princeton subject headings:
Communism--History--20th century.
Nineteen sixty-eight, A.D.
Protest movements--History--20th century.
Social movements--Germany--History--20th century.
Social movements--History--20th century.
Socialism--Germany--History--20th century.
Socialism--History--20th century.