https://hal-upec-upem.archives-ouvertes.fr/hal-00619322 Contributor : Marie-Pierre BéalConnect in order to contact the contributor Submitted on : Tuesday, September 6, 2011 - 10:36:05 AM Last modification on : Saturday, January 15, 2022 - 3:58:19 AM Long-term archiving on: : Wednesday, December 7, 2011 - 2:25:28 AM