https://cel.archives-ouvertes.fr/cel-00376389 Contributor : Cimpa CimpaConnect in order to contact the contributor Submitted on : Friday, April 17, 2009 - 2:28:55 PM Last modification on : Tuesday, October 19, 2021 - 11:00:16 AM Long-term archiving on: : Friday, October 12, 2012 - 4:50:42 PM