Columbia subject headings:
Harvard subject headings:
China--Foreign relations--20th century.
China--Foreign relations--Mongolia.
Mongolia--Foreign relations--China.
Mongolia--Foreign relations--Soviet Union.
Soviet Union--Foreign relations--Mongolia.
Princeton subject headings:
China--Foreign relations--20th century.
China--Foreign relations--Mongolia.
Mongolia--Foreign relations--China.
Mongolia--Foreign relations--Soviet Union.
Soviet Union--Foreign relations--Mongolia.