1. Water quality—Sampling—Part 5: Guidance on Sampling of Drinking Water and Water Used for Food and Beverage Processing (ISO 5667-5),1991
2. Council Directive 98/83/EG on the Quality of Water Intended for Human Consumption,1998
3. Water quality—Detection and Enumeration of Escherichia coli and Coliform bacteria—Part 1: Membrane Filtration Method (ISO 9308-1),2000
4. Water quality—Detection and Enumeration of Intestinal Enterococci—Part 2: Membrane Filtration Method (ISO 7899-2),2000
5. Anon, 2001a. Resolution for amendment of the Drinking water Act with reference to the guideline concerning the quality of water intended for human consumption. Staatsblad van het Koninkrijk der Nederlanden 31 (in Dutch).