Columbia subject headings:
Soviet Union--History--Revolution, 1917-1921.
Harvard subject headings:
Kommunisticheskai︠a︡ partii︠a︡ Sovetskogo Soi︠u︡za--History.
Rabochai︠a︡ oppozit︠s︡ii︠a︡ (Political party)
Soviet Union--History--Revolution, 1917-1921.
Princeton subject headings:
Communism--Soviet Union--History--20th century.
Rossiĭskai︠a︡ kommunisticheskai︠a︡ partii︠a︡ (bolʹshevikov)--History.
Soviet Union--History--Revolution, 1917-1921.
Soviet Union--Politics and government--1917-1936.