Columbia subject headings:
Canada--Foreign economic relations--United States.
Corporations, Foreign--Canada.
United States--Foreign economic relations--Canada.
Harvard subject headings:
Canada--Foreign economic relations--United States.
Corporations, Foreign--Canada.
United States--Foreign economic relations--Canada.
Princeton subject headings:
Canada--Foreign economic relations--United States.
Corporations, Foreign--Canada.
United States--Foreign economic relations--Canada.