Astron. Astrophys. 353, 108-116 (2000)

Acknowledgements

We would like to thank the referee for his helpful comments. This work was supported by the Deutsche Forschungsgemeinschaft through the grant LE 1039/2-1, 3-1 and the NATO Scientific Collaboration Grants program. GTB also gratefully acknowledges support by the AvH foundation through a Fedor Lynen fellowship, in the course of which substantial parts of this contribution were developed. PPK acknowledges support from the Natural Science and Engineering Research Council of Canada, and of a Killam Fellowship.

© European Southern Observatory (ESO) 2000

Online publication: December 8, 1999
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