Based on spectral observations collected at the National Astronomical Observatory at Rozhen and photometric observations collected at Mt. Laguna Observatory operated by San Diego State University, research was supported in part by the NATO Linkage grant No. PST.CLG.978810, grant No. 8/2003 of the Shoumen University, a Cottrell College Science Award of the Research Corporation, and grants from NASA and the Gaposchkin Fund administered by the AAS Small Grants Program.

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Photometric and spectroscopic data are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/424/993

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...

Figures 2-7 and Figs. 9-16 are only available in electronic form at http://www.edpsciences.org

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