Columbia subject headings:
Canada--Commerce--United States.
United States--Commerce--Canada.
United States--Commerce--West Indies, British.
West Indies, British--Commerce--United States.
Harvard subject headings:
Canada--Commerce--United States.
East Indies--Commerce--United States.
Tariff--Canada
Tariff--East Indies.
Tariff--United States.
Tariff--West Indies, British.
United States--Commerce--Canada.
United States--Commerce--East Indies.
United States--Commerce--West Indies, British.
West Indies, British--Commerce--United States.
Princeton subject headings:
Canada--Commerce--United States.
United States--Commerce--Canada.
United States--Commerce--West Indies, British.
West Indies, British--Commerce--United States.