Columbia subject headings:
Harvard subject headings:
Canada--Commercial policy--Congresses.
Canada--Foreign economic relations--United States--Congresses.
Foreign trade regulation--Congresses
Free trade--Congresses
Protectionism--Congresses.
United States--Foreign economic relations--Canada--Congresses.
Princeton subject headings:
Canada--Commercial policy--Congresses.
Free trade--Canada--Congresses.
Protectionism--Canada--Congresses.