1. Willem Salet is Professor Emeritus in Urban and Regional Planning in the Department of Planning, Geography and International Development Studies, Faculty of Social and Behavioral Sciences, University of Amsterdam, Nieuwe Achtergracht 166 Amsterdam, Amsterdam 1018WV, Netherlands;.
2. Tom Coppens is Professor at the University of Antwerp, Faculty of Design Sciences, Mutsaardstraat 28, Antwerpen 2000, Belgium;.