1. Jet Propulsion Laboratory; California Institute of Technology; Pasadena; California; USA
2. Institute for Geophysics, Jackson School of Geosciences; University of Texas at Austin; Austin; Texas; USA
3. Southwest Research Institute; Boulder; Colorado; USA
4. Department of Geological Sciences; Brown University; Providence; Rhode Island; USA
5. INFOCOM Department; University of Rome; Rome; Italy
6. Dipartimento di Scienze della Terra; Università degli Studi di Perugia; Perugia; Italy