Columbia subject headings:
Harvard subject headings:
China--History--221 B.C.-960 A.D.
China--History--Song dynasty, 960-1279.
China--History--To 221 B.C.
Princeton subject headings:
China--History--221 B.C.-960 A.D.
China--History--Song dynasty, 960-1279.
China--History--Warring States, 403-221 B.C.