1. Faculty of Applied Economics and StatUa Center for Statistics; Universiteit Antwerpen; Prinsstraat 13 2000 Antwerp Belgium
2. JMP Division; SAS Institute Inc.; SAS Campus Drive Cary NC 27513 USA
3. Faculty of Bioscience Engineering; Katholieke Universiteit Leuven; Kasteelpark Arenberg 30 3001 Leuven Belgium