Columbia subject headings:
Harvard subject headings:
Greece--Relations--Russia--Congresses.
Greece--Relations--Soviet Union--Congresses.
Russia--Relations--Congresses.
Soviet Union--Relations--Greece--Congresses.
Princeton subject headings:
Greece--Relations--Russia--Congresses.
Greece--Relations--Soviet Union--Congresses.
Russia--Relations--Greece--Congresses.
Soviet Union--Relations--Greece--Congresses.