1. Department of Transport and Regional Economics, Faculty of Applied Economics, University of Antwerp; Prinsstraat 13 2000 Antwerpen Belgium
2. Centre for Digital Music, School of Electronic Engineering and Computer Science, Queen Mary University of London; Mile End Road London E1 4NS United Kingdom
3. ANT/OR Operations Research Group, Faculty of Applied Economics, University of Antwerp; Prinsstraat 13 2000 Antwerpen Belgium