https://cel.archives-ouvertes.fr/cel-00651862 Contributor : Sylvie FloresConnect in order to contact the contributor Submitted on : Wednesday, December 14, 2011 - 1:44:51 PM Last modification on : Thursday, December 15, 2011 - 10:19:35 AM Long-term archiving on: : Thursday, March 15, 2012 - 2:36:01 AM