1. Faculty of Electrical Engineering, University of Ljubljana, Tržaška Cesta 25, SI-1000 Ljubljana, Slovenia
2. IMFM, Jadranska Cesta 19, SI-1000 Ljubljana, Slovenia
3. Faculty of Algebra, Department of Mechanics and Mathematics, Lomonosov Moscow State University, Moscow 119991, Russia
4. Moscow Institute of Physics and Technology, Dolgoprudny, 141701, Russia
5. University of Primorska, FAMNIT, Glagoljaška 8, SI-6000 Koper, Slovenia