https://cel.archives-ouvertes.fr/cel-00420490 Contributor : Cimpa CimpaConnect in order to contact the contributor Submitted on : Tuesday, January 12, 2010 - 11:34:03 AM Last modification on : Tuesday, October 19, 2021 - 11:34:29 PM Long-term archiving on: : Thursday, September 23, 2010 - 11:04:49 AM