‘Isotope Tracers in Catchment Hydrologie’, ‘Environmental isotopes in Hydrogeology’, ‘Environmental impact of land use in rural regions’, ‘Hydrological Sciences: Taking Stock and Looking Ahead. Regionalization in hydrology’
4 januari 1999 Michael van der Valk. Koos Groen. Harry Boukes. Michael van der Valk. Michael van der Valk Editie 1999 - 4
