Affiliation: | a Observatoire de la Côte d'Azur, B.P. 4229, Nice Cedex 4, 06304, Francef1michel@obs-nice.frf1b Physikalisches Institut, University of Bern, Sidlerstrasse 5, Bern, CH-3012, Switzerlandc Observatoire de la Côte d'Azur, B.P. 4229, Nice Cedex 4, 06304, Franced Department of Astronomy, University of Maryland, College Park, Maryland, 20742-2421 |