http://hal.in2p3.fr/in2p3-00022139 Contributor : Claudine BombarConnect in order to contact the contributor Submitted on : Thursday, July 29, 2004 - 5:22:43 PM Last modification on : Friday, November 6, 2020 - 3:29:27 AM Long-term archiving on: : Thursday, April 1, 2010 - 2:43:24 PM