Columbia subject headings:
Communism--Europe, Eastern--History.
Europe, Eastern--History.
Soviet Union--History--Revolution, 1917-1921--Influence.
Harvard subject headings:
Communism--Europe, Central--History.
Communism--Europe, Eastern--History
Europe, Central--History.
Europe, Eastern--History.
Soviet Union--History--Revolution, 1917-1921--Influence.
Princeton subject headings:
Communism--Europe, Eastern--History.
Europe, Eastern--History.
Soviet Union--History--Revolution, 1917-1921--Influence.