https://hal-ens-lyon.archives-ouvertes.fr/ensl-00767529 Contributor : Vincent CharbonnierConnect in order to contact the contributor Submitted on : Thursday, December 20, 2012 - 6:23:40 AM Last modification on : Wednesday, March 9, 2022 - 3:28:02 PM Long-term archiving on: : Thursday, March 21, 2013 - 3:47:03 AM