Columbia subject headings:
Electricity--Mexico--Maps.
Gas industry--Mexico--Maps.
Maps.
Petroleum industry and trade--Mexico--Maps.
Petroleum--Mexico--Maps.
Pipelines--Mexico--Maps.
Power resources--Mexico--Maps.
Harvard subject headings:
Electricity--Mexico--Maps.
Gas industry--Mexico--Maps.
Petroleum industry and trade--Mexico--Maps.
Petroleum--Mexico--Maps.
Pipelines--Mexico--Maps.
Power resources--Mexico--Maps.
Princeton subject headings: