Columbia subject headings:
Europe--History--1918-1945.
Revolutions--Europe--History--20th century.
Soviet Union--History--Revolution, 1917-1921--Influence.
Harvard subject headings:
Europe--History--1918-1945.
Revolutions--Europe--History--20th century.
Soviet Union--History--Revolution, 1917-1921--Influence.
Princeton subject headings:
Europe--History--20th century.
Soviet Union--History--Revolution, 1917-1921--Influence.