1. Van der Waals-Zeeman Institute, University of Amsterdam Valckenierstraat 65, 1018 XE Amsterdam, The Netherlands
2. B. Verkin Institute for Low Temperature Physics, Kharkov, 310164, Ukraine
3. Helax AB, Box 1704, 751 47 Uppsala, Sweden
4. Kure National College of Technology, 2-2-11 Agaminami, Kure 737, Japan