Columbia subject headings:
Soviet Union--Foreign relations--Yemen (Republic)
Yemen, South--Foreign relations--Soviet Union.
Yemen, South--Politics and government.
Harvard subject headings:
Soviet Union--Foreign relations--Yemen, South.
Yemen (People's Democratic Republic)--Foreign relations--Soviet Union.
Yemen (People's Democratic Republic)--Politics and government.
Princeton subject headings:
Soviet Union--Foreign relations--Yemen (People's Democratic Republic).
Yemen (People's Democratic Republic)--Foreign relations--Soviet Union.
Yemen (People's Democratic Republic)--Politics and government.