Columbia subject headings:
Harvard subject headings:
Canada--Foreign economic relations--United States--Congresses.
Free trade--Canada--Congresses
Free trade--North America--Congresses
Free trade--United States--Congresses
North America--Economic integration--Congresses.
North American Free Trade Agreement--Congresses.
United States--Foreign economic relations--Canada--Congresses.
Princeton subject headings:
Free trade--Canada--Congresses.
Free trade--North America--Congresses.
North America--Economic integration--Congresses.