https://cel.archives-ouvertes.fr/cel-00392289 Contributor : Yvan VelenikConnect in order to contact the contributor Submitted on : Saturday, June 6, 2009 - 3:42:42 PM Last modification on : Monday, March 14, 2022 - 4:52:06 PM Long-term archiving on: : Monday, October 15, 2012 - 12:00:44 PM