Columbia subject headings:
Hungary--History--Revolution, 1918-1919--Congresses.
Soviet Union--History--Revolution, 1917-1921--Influence--Congresses.
Harvard subject headings:
Hungary--History--Revolution, 1918-1919--Congresses.
Soviet Union--History--Revolution, 1917-1921--Influence--Congresses.
Princeton subject headings:
Hungary--History--Revolution, 1918-1919.
Hungary--Relations--Soviet Union.
Soviet Union--Relations--Hungary.