Columbia subject headings:
Natural gas reserves--Economic aspects--Africa, North.
Natural gas reserves--Economic aspects--Middle East.
Harvard subject headings:
Natural gas reserves--Economic aspects--Africa, North.
Natural gas reserves--Economic aspects--Middle East.
Princeton subject headings:
Gas industry--Africa, North.
Gas industry--Middle East.
Natural gas reserves--Economic aspects--Africa, North.
Natural gas reserves--Economic aspects--Middle East.
Natural gas--Africa, North.
Natural gas--Middle East.