1. Institute of Physics, Mathematics and Information Technology, Immanuel Kant Baltic Federal University, 236041 Kaliningrad, Russia
2. Faculty of Computational Mathematics and Cybernetics, Lomonosov Moscow State University, 119991 Moscow, Russia
3. Department of Astrophysics/IMAPP,Radboud University Nijmegen, NL-6500 GL Nijmegen, The Netherlands