Columbia subject headings:
Organization of Petroleum Exporting Countries.
Petroleum as fuel--Prices--United States.
Petroleum products--Prices--United States.
Harvard subject headings:
Organization of Petroleum Exporting Countries.
Petroleum as fuel--Prices--United States.
Petroleum products--Prices--United States
Princeton subject headings:
Organization of Petroleum Exporting Countries.
Petroleum as fuel--Prices--United States.
Petroleum products--Prices--United States.