https://cel.archives-ouvertes.fr/cel-00392215 Contributor : Cimpa CimpaConnect in order to contact the contributor Submitted on : Friday, June 5, 2009 - 5:08:09 PM Last modification on : Saturday, January 15, 2022 - 4:13:17 AM Long-term archiving on: : Monday, October 15, 2012 - 12:02:18 PM