https://hal-sfo.ccsd.cnrs.fr/sfo-00658678 Contributor : Saïda GuellatiConnect in order to contact the contributor Submitted on : Tuesday, January 10, 2012 - 10:37:02 PM Last modification on : Wednesday, November 17, 2021 - 12:29:12 PM Long-term archiving on: : Monday, November 19, 2012 - 1:10:16 PM