Columbia subject headings:
Harvard subject headings:
Soviet Union--Foreign relations--1945-1991.
Soviet Union--Foreign relations--Yemen, North.
Soviet Union--Foreign relations--Yemen, South.
Yemen (Arab Republic)--Foreign relations--Soviet Union.
Yemen (People's Democratic Republic)--Foreign relations--Soviet Union.
Princeton subject headings:
Soviet Union--Foreign relations--1945-1991.
Soviet Union--Foreign relations--Yemen (People's Democratic Republic).
Soviet Union--Foreign relations--Yemen.
Yemen (People's Democratic Republic)--Foreign relations--Soviet Union.
Yemen--Foreign relations--Soviet Union.