Columbia subject headings:
Petroleum industry and trade--Government policy--Mexico--History.
Petroleum industry and trade--Mexico--History.
Petroleum law and legislation--Mexico.
Harvard subject headings:
Energy policy--Mexico--History.
Petroleum industry and trade--Mexico--History.
Petroleum--Prospecting--Mexico--History.
Princeton subject headings:
Energy policy--Mexico--History.
Petroleum industry and trade--Mexico--History.
Petroleum--Prospecting--Mexico--History.