Columbia subject headings:
Harvard subject headings:
China--Foreign relations--To 1644.
China--History--Han dynasty, 202 B.C.-220 A.D.
China--History--Tang dynasty, 618-907.
Princeton subject headings:
China--Foreign relations--To 1644.
China--History--Han dynasty, 202 B.C.-220 A.D.
China--History--Tang dynasty, 618-907.