Columbia subject headings:
Harvard subject headings:
Communism--Soviet Union--History
Communist parties--Soviet Union.
Kommunisticheskai︠a︡ partii︠a︡ Sovetskogo Soi︠u︡za.
Social reformers--Soviet Union.
Socialist parties--Soviet Union.
Soviet Union--Politics and government--1917-1936.
Princeton subject headings:
Communism--History.
Socialism--History.