Contents : Early Contactor Involvement in Dutch Infrastructure Development : Initial Experiences with Parallel Procedures for Planning and Procurement S.Lenferink, J.Arts, T.Tillema, M.van Valkenburg and R.Nijsten Environmental Impacts and The Most Economically Advantageous Tender in Public Procurement K.Parikka-Alhola and A.Nissinen Combinatorial Auctions in Public Procurement : Exp…