Institution: | 1.Department of Economics and Management, Wageningen Agricultural University, Hollandseweg 1, 6706 KN, Wageningen, the Netherlands ;2.Animal Health Service, PO Box 9, 7400 AA, Deventer, the Netherlands ;3.Department of Farm Animal Health, Faculty of Veterinary Medicine, University Utrecht, PO Box 80.151, 3508 TD, Utrecht, the Netherlands ; |