References for the numbering systems

Col	Reference

--- ---------

R1 Yilmaz F. 1970, Astron. Astrophys. 8, 213

R2 Petry C., et al. 1994, priv. comm.

R3 Subramaniam A., Bhatt B.C. 2007, Mon. Not. R. Astron. Soc. 377, 829

R4 Viskum M., et al. 1997 Astron. Astrophys. 328, 158

R5 Glushkova E.V., et al. 2010, Astron. Lett. 36, 14

R6 Janes K.A., Hoq S. 2011, Astron. J. 141, 92


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