Columbia subject headings:
Arab countries--Economic conditions.
Arab countries--Environmental conditions.
Land use--Arab countries.
Water-supply--Arab countries.
Harvard subject headings:
Arab countries--Economic conditions.
Arab countries--Environmental conditions.
Land use--Arab countries.
Water-supply--Arab countries
Princeton subject headings:
Arab countries--Economic conditions.
Arab countries--Environmental conditions.
Land use--Arab countries.
Water-supply--Arab countries.