Columbia subject headings:
Harvard subject headings:
Mexico--Commerce--United States--History.
Mexico--Commercial policy--History.
Mexico--Foreign economic relations--United States--History.
United States--Commerce--Mexico--History.
United States--Foreign economic relations--Mexico.
Princeton subject headings:
Mexico--Commerce--United States--History.
Mexico--Commercial policy--History.
Mexico--Foreign economic relations--United States--History.
United States--Commerce--Mexico--History.
United States--Foreign economic relations--Mexico.