1. M. J. M. Volman, PhD, is Assistant Professor, Department of General and Special Education, Utrecht University, PO Box 80140, 3508 TC Utrecht, the Netherlands; m.volman@fss.uu.nl
2. Brecht M. van Schendel, MSc, is Lecturer, School of Education, Fontys Hogeschool, Den Bosch, the Netherlands
3. Marian J. Jongmans, PhD, is Full Professor, Department of General and Special Education, Utrecht University, the Netherlands