Columbia subject headings:
Europe--History--1789-1900.
Europe--History--20th century.
Intellectuals.
Socialism.
Soviet Union--History.
Harvard subject headings:
Europe--History--1789-1900.
Europe--History--20th century.
Intellectuals.
Socialism.
Soviet Union--History.
Princeton subject headings:
Europe--History--1789-1900.
Europe--History--20th century.
Intellectuals.
Socialism.
Soviet Union--History.