https://cel.archives-ouvertes.fr/cel-00392119 Contributor : Cimpa CimpaConnect in order to contact the contributor Submitted on : Friday, June 5, 2009 - 3:17:54 PM Last modification on : Tuesday, August 11, 2020 - 9:52:15 AM Long-term archiving on: : Friday, June 11, 2010 - 12:23:00 AM