Columbia subject headings:
Great Britain--Foreign relations--Mexico.
Mexico--Foreign relations--Great Britain.
Mexico--Foreign relations--United States.
Petroleum industry and trade--Mexico.
Petroleum law and legislation--Mexico.
United States--Foreign relations--Mexico.
Harvard subject headings:
Great Britain--Foreign relations--Mexico.
Mexico--Foreign relations--Great Britain.
Mexico--Foreign relations--United States.
Petroleum industry and trade--Mexico
Petroleum law and legislation--Mexico.
United States--Foreign relations--Mexico.
Princeton subject headings: