Columbia subject headings:
Harvard subject headings:
Water quality management--European Union countries--Periodicals.
Water--Pollution--European Union countries--Periodicals.
Water-supply--European Union countries--Periodicals.
Princeton subject headings:
Periodicals.
Water quality management--Europe Union countries--Periodicals.
Water--Pollution--European Union countries--Periodicals.
Water-supply--European Union countries--Periodicals.