1. Centre interuniversitaire de recherche sur les réseaux d'entreprise, la logistique et le transport (CIRRELT), FORAC Research Consortium, Université Laval, G1K 7P4, Québec, Canada
2. The Norwegian School of Economics and Business Administration, Bergen, Norway and The Forestry Research Institute of Sweden, Uppsala, Sweden
3. Department of Industrial Engineering, University of Chile, Santiago, Chile