Tables 3 to
10 and Figs. 6 to 11 are only available in electronic version at
http://www.edpsciences.com
Tables 7, 8, 9 are also available in electronic version
form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via
http://cdsweb.u-strasbg.fr/Abstract.html
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.