1. School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455, USA.
2. AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, 30-059 Krakow, Poland.
3. National High Magnetic Field National Laboratory, Florida State University, 1800 E. Paul Dirac Drive, Tallahassee, FL 32310, USA.
4. Institute of Solid State Physics, TU Wien, 1040 Vienna, Austria.
5. Department of Physics, Faculty of Science, University of Zagreb, HR-10000 Zagreb, Croatia.