Columbia subject headings:
Science--Hungary--History--Congresses.
Science--International cooperation--History--Congresses.
Science--Soviet Union--History--Congresses.
Technology--Hungary--History--Congresses.
Technology--Soviet Union--History--Congresses.
Harvard subject headings:
Science--Hungary--History--Congresses.
Science--International cooperation--History--Congresses.
Science--Soviet Union--History--Congresses.
Technology--Hungary--History--Congresses.
Technology--Soviet Union--History--Congresses.
Princeton subject headings: