Columbia subject headings:
Agriculture and state--Soviet Union--Congresses.
Industries--Soviet Union--Congresses.
Soviet Union--History--Congresses.
Soviet Union--Rural conditions--Congresses.
Soviet Union--Social conditions--Congresses.
Working class--Soviet Union--Congresses.
Harvard subject headings:
Agriculture and state--Soviet Union--Congresses.
Industries--Soviet Union--Congresses.
Soviet Union--History--Congresses.
Soviet Union--Rural conditions--Congresses.
Soviet Union--Social conditions--Congresses.
Working class--Soviet Union--Congresses.
Princeton subject headings: