Columbia subject headings:
Harvard subject headings:
Drinking water
Europe.
Legislation
Water microbiology.
Water quality.
Water--Pollution
Water--Purification
Water-supply
Princeton subject headings:
Drinking water--Health aspects--Europe.
Drinking water.
Legislation.
Water quality--Health aspects--Europe.
Water quality.
Water--Microbiology.
Water--Pollution--Europe--Physiological effect.
Water--Pollution.
Water--Purification--Health aspects--Europe.
Water--Purification.
Water-supply--Health aspects--Europe.
Water-supply.