References for the numbering systems

Col	Reference

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

R1	Purgathofer A. 1964, Ann. Univ. Sternw. Wien 26 no 2

R2	Balaguer-Nunez L., et al. 1998, Astron. Astrophys. Suppl. 133, 387

R3	Balaguer-Nunez L., et al. 2004, Astron. Astrophys. 426, 827

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