...1991
based on data collected at the European Southern Observatory, La Silla, Chile.
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...1991
Tables and the complete data set are also available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr or via http://cdsweb.u-strasbg.fr/Abstract.html
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...levels
Figure 1 to 24 are only available on the on-line version of A&A at http://www.ed-phys.fr
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Copyright by the European Southern Observatory (ESO)
web@ed-phys.fr