Columbia subject headings:
China--Economic conditions--To 1644.
China--History--Xi Xia dynasty, 1038-1227.
Harvard subject headings:
China--Economic conditions--To 1644
China--History--Xi Xia dynasty, 1038-1227
Princeton subject headings:
China--Economic conditions--To 1644.
China--History--Xi Xia dynasty, 1038-1227.