Columbia subject headings:
Communism--Europe, Eastern.
Communism--Soviet Union.
Working class--Political activity--Europe, Eastern.
Working class--Political activity--Soviet Union.
Harvard subject headings:
Communism--Europe, Eastern
Communism--Soviet Union
Working class--Europe, Eastern--Political activity.
Working class--Political activity--Europe, Eastern.
Working class--Political activity--Soviet Union.
Working class--Soviet Union--Political activity.
Princeton subject headings:
Communism--Europe, Eastern.
Communism--Soviet Union.
Working class--Europe, Eastern--Political activity.
Working class--Soviet Union--Political activity.