1. UNESCO-IHE Institute for Water Education, P. O. Box 3015, 2601 DA, Delft, The Netherlands (E-mail: b.petrusevski@unesco-ihe.org)
2. VITENS. P. O. Box 400, 8901 BE, Leeuwarden, The Netherlands (E-mail: walter.vandermeer@vitens.nl)
3. SELOR, Saffierstraat 101C, 1074BP, Amsterdam, The Netherlands (E-mail: selor@tiscali.nl)