1. University of Modena and Reggio Emilia, FIM, via G. Campi 213/b, 41125 Modena, Italy
2. Instituto Superior Técnico, CAMGSD, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
3. Technische Universiteit Delft, DIAM, P.O. Box 5031, 2600 GA Delft, The Netherlands