Columbia subject headings:
Coal--United States.
Natural gas--United States.
Petroleum--United States.
Power resources--United States.
Uranium--United States.
Harvard subject headings:
Coal--United States
Natural gas--United States
Petroleum--United States
Power resources--United States
Uranium--United States.
Princeton subject headings:
Coal--United States.
Natural gas--United States.
Petroleum--United States.
Power resources--United States.
Uranium--United States.