https://cel.archives-ouvertes.fr/cel-00376317 Contributor : Cimpa CimpaConnect in order to contact the contributor Submitted on : Friday, April 17, 2009 - 11:54:39 AM Last modification on : Wednesday, March 9, 2022 - 3:12:02 PM Long-term archiving on: : Friday, October 12, 2012 - 4:50:28 PM