https://cel.archives-ouvertes.fr/cel-00346023 Contributor : Franck LaloëConnect in order to contact the contributor Submitted on : Friday, December 12, 2008 - 5:03:21 PM Last modification on : Thursday, March 17, 2022 - 10:08:07 AM Long-term archiving on: : Tuesday, June 8, 2010 - 4:04:25 PM