Columbia subject headings:
Energy policy--United States.
Imports--United States.
Petroleum industry and trade--Government policy--United States.
Petroleum industry and trade--Political aspects--United States.
Harvard subject headings:
Energy policy--United States
Imports--United States
Petroleum industry and trade--Government policy--United States
Petroleum industry and trade--Political aspects--United States
Princeton subject headings:
Energy policy--United States.
Imports--United States.
Petroleum industry and trade--Government policy--United States.
Petroleum industry and trade--Political aspects--United States.