 |
 |
Astron. Astrophys. 345, 307-314 (1999)
Acknowledgements
The authors thank I.G. Kovalenko, V.M. Lipunov, V.V. Mustsevoj and M.E. Prokhorov for fruitful discussions and valuable comments. This research is partially supported by Fund INTAS, grant number 95-0988.
© European Southern Observatory (ESO) 1999
Online publication: April 12, 1999
helpdesk.link@springer.de