1. Panchuk, V.E., Tavolzhanskaya, N.S., and Chepizhko, A.V., Bull. Spec. Astrophys. Obs., 1996, vol. 41, p. 154.
2. Panchuk, V.E., Klochkova, V.G., and Yushkin, M.V., Astron. Rep., 2017, vol. 61, no. 9, p. 820. https://doi.org/10.1134/s1063772917080091
3. Panchuk, V.E., Chuntonov, G.A., and Naidenov, I.D., Astrophys. Bull., 2014, vol. 69, no. 3, p. 339. https://doi.org/10.1134/s1990341314030109
4. Schroeder, D.J., Publ. Astron. Soc. Pac., 1970, vol. 82, no. 490, p. 1253.
5. Barden, S.C., Astronomical Society of the Pacific Conference Series, vol. 3, Proc. Conference, Tucson, April 11–14, 1988, Barden, S.C., Ed., San Francisco, CA: Astronomical Society of the Pacific (ASP), 1988.