Columbia subject headings:
Petroleum industry and trade--United States--Statistics--Periodicals.
Power resources--United States--Statistics--Periodicals.
Harvard subject headings:
Petroleum industry and trade--United States--Statistics--Periodicals
Power resources--United States--Statistics--Periodicals
Princeton subject headings:
Periodicals.
Petroleum industry and trade--United States--Periodicals.
Power resources--United States--Periodicals.