Columbia subject headings:
Customs unions.
Free trade--America.
Latin America--Foreign economic relations--United States.
United States--Foreign economic relations--Latin America.
Harvard subject headings:
Customs unions--America.
Customs unions.
Free trade--America
Latin America--Foreign economic relations--United States.
United States--Foreign economic relations--Latin America.
Princeton subject headings:
Customs unions.
Free trade--America.
Latin America--Foreign economic relations--United States.
United States--Foreign economic relations--Latin America.