Columbia subject headings:
Canada--Boundaries--United States.
Canada--Foreign relations--United States.
United States--Boundaries--Canada.
Harvard subject headings:
Canada--Boundaries--United States.
Canada--Foreign relations--United States.
United States--Boundaries--Canada.
United States--Foreign relations--Canada.
Princeton subject headings:
Canada--Boundaries--United States.
Canada--Foreign relations--United States.
United States--Boundaries--Canada.
United States--Foreign relations--Canada.