Columbia subject headings:
South America--Commerce--United States.
South America--Description and travel.
South America--Economic conditions.
United States--Commerce--South America.
Harvard subject headings:
South America--Commerce--United States.
South America--Description and travel.
South America--Economic conditions.
United States--Commerce--South America.
Princeton subject headings:
South America--Commerce--United States.
South America--Description and travel.
South America--Economic conditions.
United States--Commerce--South America.