Columbia subject headings:
China--History--Song dynasty, 960-1279.
China--History--Tang dynasty, 618-907.
Law--China--History.
Harvard subject headings:
China--Politics and government--581-907
China--Politics and government--960-1279.
Law--China--History
Princeton subject headings:
China--History--Song dynasty, 960-1279.
China--History--Tang dynasty, 618-907.
Law--China--History.