References for the numbering systems

Col	Reference

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

R1	Haug U. 1978, Astron. Astrophys. Suppl. 34,417

R2	Lindoff U. 1968, Ark. Astr. 4, 471

R3	Kjeldsen H., Frandsen S. 1991, Astron. Astrophys. Suppl. 87, 119

R4	Carraro G., Munari U. 2004, Mon. Not. R. Astron. Soc. 347, 625

R5	Ahumada J.A. 2005, Astron. Nachr. 326, 3

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