Institute for System Dynamics, University of Stuttgart, Stuttgart, Germany.|Institute for System Dynamics, University of Stuttgart, Stuttgart, Germany.|Institute for System Dynamics, University of Stuttgart, Stuttgart, Germany.|Institute for System Dynamics, University of Stuttgart, Stuttgart, Germany.|Institute for System Dynamics, University of Stuttgart, Stuttgart, Germany.|Institute for System Dynamics, University of Stuttgart, Stuttgart, Germany.|Institute for System Dynamics, University of Stuttgart, Stuttgart, Germany.|Institute for System Dynamics, University of Stuttgart, Stuttgart, Germany.|Institute for System Dynamics, University of Stuttgart, Stuttgart, Germany.