https://hal.archives-ouvertes.fr/hal-00879624 Contributor : Serge BeucherConnect in order to contact the contributor Submitted on : Monday, November 4, 2013 - 2:22:51 PM Last modification on : Wednesday, November 17, 2021 - 12:27:12 PM Long-term archiving on: : Friday, April 7, 2017 - 8:31:22 PM