https://hal-pjse.archives-ouvertes.fr/hal-00616993 Contributor : Xavier FontaineConnect in order to contact the contributor Submitted on : Thursday, August 25, 2011 - 1:24:42 PM Last modification on : Friday, April 29, 2022 - 10:12:58 AM Long-term archiving on: : Monday, November 12, 2012 - 3:51:27 PM