https://cel.archives-ouvertes.fr/cel-00376452 Contributor : Cimpa CimpaConnect in order to contact the contributor Submitted on : Friday, April 17, 2009 - 3:20:00 PM Last modification on : Monday, June 28, 2021 - 2:26:03 PM Long-term archiving on: : Thursday, June 10, 2010 - 6:57:56 PM