Columbia subject headings:
Free trade--Political aspects--North America.
Free trade--Social aspects--North America.
North America--Economic integration.
North American Free Trade Agreement
Harvard subject headings:
Free trade--North America
Free trade--Political aspects--North America.
Free trade--Social aspects--North America.
North America--Economic integration
North American Free Trade Agreement
Princeton subject headings:
Free trade--Political aspects--North America.
Free trade--Social aspects--North America.
North America--Economic integration.