1. LIPN, Paris-XIII and UMR 7030, France; ANR project MAGNUM, Olivier.Bodini@lip6.fr
2. PRiSM, Université Versailles St Quentin, CNRS UMR 8144, France, gardy@prism.uvsq.fr
3. LIP6, Paris-VI and UMR 7606, France; ANR project MAGNUM, olivier.roussel@lip6.fr