1. I. Yu. Alekseev and A. V. Kozhevnikova, Astrofizika 47, 519 (2004).
2. S. S. Vogt and A. P. Hatzes, The Sun and Cool Stars: Activity, Magnetism, Dynamos, eds. I. Tuominen, D. Moss, and G. Rüdiger, Springer-Verlag (1991), p. 297.
3. S. W. Wacker, E. F. Guinan, G. P. McCook, et al., Inform. Bull. Var. Stars 2920 (1986).
4. S. Mohin and A. V. Raveendran, J. Astrophys. Astron. 10, 35 (1989).
5. A. V. Raveendran and S. Mohin, Astron. Astrophys. 301, 708 (1995).