1. L.W. Acton, M.L. Finch, C.W. Gilbreth, J.L. Culhane, R.D. Bentley, J.A. Bowles, P. Guttridge, A.H. Gabriel, J.G. Firth, R.W. Hayes, Sol. Phys. 65, 53 (1980)
2. L.A. Akimov, S.A. Beletskii, I.L. Belkina, O.I. Bugaenko, Y.I. Velikodskii, I.A. Zhitnik, A.P. Ignat’ev, V.V. Korokhin, S.V. Kuzin, G.P. Marchenko, A.A. Pertsov, Astron. Rep. 49, 579 (2005)
3. L.A. Akimov, C.A. Beletski, I.L. Belkina, O.I. Bugaenko, Yu.I. Velikodski, I.A. Zhitnik, A.P. Ignat’ev, V.V. Korohin, S.V. Kuzin et al., Astronomicheskij zhurnal 49, 579 (2005), in russian
4. L.A. Akimov, I.L. Belkina, S.V. Kuzin, A.A. Pertsov, I.A. Zhitnik, Astron. Lett. 34, 851 (2008)
5. L.A. Akimov, I.L. Belikina, S.V. Kuzin et al., Pis’ma v Astronomicheskij zhurnal 34, 1 (2008), in russian