Columbia subject headings:
Harvard subject headings:
China--Commerce--England--History--18th century.
China--Commerce--England--History--19th century.
England--Commerce--China--History--18th century.
England--Commerce--China--History--19th century.
Opium--Government policy--China--History--18th century.
Opium--Government policy--China--History--19th century.
Princeton subject headings:
China--Commerce--England--History--18th century.
China--Commerce--England--History--19th century.
England--Commerce--China--History--18th century.
England--Commerce--China--History--19th century.
Opium--Government policy--China--History--18th century.
Opium--Government policy--China--History--19th century.