1. Jordforsk - Norwegian Centre for Soil and Environmental Research, N-1432 Ås, Norway (E-mail: per.stalnacke@jordforsk.no)
2. Jordforsk - Norwegian Centre for Soil and Environmental Research, N-1432 Ås, Norway (E-mail: stine.vandsemb@jordforsk.no)
3. Tallinn Technical University, Department of Environmental Engineering, EE-0026 Tallinn, Estonia (E-mail: avasil@cc.ttu.ee)
4. Linköping University, Department of Mathematics, SE-581 83 Linköping, Sweden (E-mail: angri@mai.liu.se)
5. VITUKI - Water Resources Research Centre Plc. Hungary (E-mail: jolankai@vituki.hu)