1. D. Hoffleit and C. Jaschek, The Bright Star Catalogue (Yale University Observatory, New Hawen USA, 1982).
2. I. Jr. Iben and A. V. Tutukov, Astrophys. J. 418, 343 (1993).
3. H. Plets, C. Waelkens, and N. R. Trams, Astronom. and Astrophys. 293, 363 (1995).
4. M. P. Fitzgerald, Astronom. and Astrophys. 4, 234 (1970).
5. van F. Leeuwen, Astronom. and Astrophys. 474, 653 (2007).