Columbia subject headings:
Czechoslovakia--Foreign relations--Soviet Union.
Czechoslovakia--History--Intervention, 1968.
Soviet Union--Foreign relations--Czechoslovakia.
Harvard subject headings:
Czechoslovakia--Foreign relations--Soviet Union.
Czechoslovakia--History--Intervention, 1968.
Soviet Union--Foreign relations--Czechoslovakia.
Princeton subject headings:
Czechoslovakia--Foreign relations--Soviet Union.
Czechoslovakia--History--Intervention, 1968.
Soviet Union--Foreign relations--Czechoslovakia.