• the Research Department of SRRC, Netherlands, enabling this study,

• the supervisors Nynke Osinga (SRRC) and Per Jensen (Linköping`s University) for helpful comments and support,

• Johannes Albrecht for ambitious help in data collection,

• many thanks to the late Renske Hekman for ambitious help in data collection, helpful comments, support and friendship,

and, finally, to all interested volunteers and visitors in Netherlands, and of course to you now visiting my webpage!