Columbia subject headings:
Harvard subject headings:
China--History--Liao dynasty, 947-1125
China--History--Song dynasty, 960-1279.
China--History--Xi Xia dynasty, 1038-1227.
Princeton subject headings:
China--History--Liao dynasty, 947-1125.
China--History--Song dynasty, 960-1279.
China--History--Xi Xia dynasty, 1038-1227.