Columbia subject headings:
China--Commerce--History.
China--Economic conditions--19th century.
China--Economic conditions--20th century.
Harbors--Economic aspects--China.
Transportation--China.
Transportation--East Asia.
Harvard subject headings:
China--Commerce--History.
China--Economic conditions--19th century.
China--Economic conditions--20th century.
Harbors--Economic aspects--China.
Princeton subject headings: