Columbia subject headings:
Canada--Commercial treaties.
Free trade--Canada.
Free trade--Mexico.
Free trade--United States.
Mexico--Commercial treaties.
North American Free Trade Agreement
United States--Commercial treaties.
Harvard subject headings:
Foreign trade regulation--United States.
Free trade--North America
Free trade--United States
North American Free Trade Agreement
Tariff--Law and legislation--North America.
United States--Commercial policy.
Princeton subject headings:
Foreign trade regulation--United States.
Free trade--North America.
Free trade--United States.
North American Free Trade Agreement
Tariff--Law and legislation--North America.
United States--Commercial policy.