Columbia subject headings:
Canada--Foreign relations--United States.
Presidents--United States--History.
Prime ministers--Canada--History.
United States--Foreign relations--Canada.
Harvard subject headings:
Canada--Foreign relations--United States.
Presidents--United States--History
Prime ministers--Canada--History.
United States--Foreign relations--Canada.
Princeton subject headings:
Canada--Foreign relations--United States.
Presidents--United States.
Prime ministers--Canada.
United States--Foreign relations--Canada.