[1] CE Saclay, CEA DSM IRFU SAp AIM, F-91191 Gif Sur Yvette, France
[2] Stanford Univ, W Hansen P L, Stanford, CA 94305 USA
[3] IAC, San Cristobal la Laguna, Spain
[4] Univ Bonn, Argelander Inst Astron, Bonn, Germany
[5] NCAR, High Altitude Observ, Boulder, CO 80307 USA
[6] LATMOS, Paris, France
[7] Univ Nice Sophia Antipolis, CNRS, Observ Cote dAzur, F-06304 Nice 4, France