https://cel.archives-ouvertes.fr/cel-00651928 Contributor : Sylvie FloresConnect in order to contact the contributor Submitted on : Wednesday, December 14, 2011 - 3:23:02 PM Last modification on : Monday, December 18, 2017 - 4:42:01 PM Long-term archiving on: : Thursday, March 15, 2012 - 2:40:14 AM