https://cel.archives-ouvertes.fr/cel-00560173 Contributor : Jean-Luc ArchimbaudConnect in order to contact the contributor Submitted on : Thursday, January 27, 2011 - 3:13:19 PM Last modification on : Thursday, January 11, 2018 - 6:19:34 AM Long-term archiving on: : Thursday, April 28, 2011 - 3:12:56 AM