1. 1Anon . (1982 ) NEN 6571: Bacteriologisch onderzoek van water - Kwantificeren van bacterien van de coligroep met behulp van membraanfiltratie . Delft, The Netherlands: NNI.
2. 2Anon . (1992 ) NEN 6559: Bacteriologisch onderzoek van water - Monsterneming en conservering . Delft, The Netherlands: NNI.
3. 3Anon . (1998 ) Council Directive 98/83/EC of 3 November 1998 on the quality of water intended for human consumption .Official Journal of the European Communities5.12.98, L330/32-L330/53.
4. 4Anon . (2000 ) Comparison of methods for drinking water bacteriology - cultural techniques. Drinking Water Inspectorate Information Letter 5/2000-10 February 2000 . UK: Drinking Water Inspectorate.
5. 5Anon . (2000 ) ISO 9308-1: Water quality - Detection and enumeration ofEscherichia coliand total coliform bacteria . Geneva, Switzerland: International Organisation for Standardisation.