https://hal-hprints.archives-ouvertes.fr/hprints-00222089 Contributor : Christian KnudsenConnect in order to contact the contributor Submitted on : Tuesday, January 29, 2008 - 11:55:13 AM Last modification on : Wednesday, January 22, 2020 - 4:44:05 PM Long-term archiving on: : Friday, April 30, 2010 - 12:59:01 AM