1. Department of Rare Earth
2. Faculty of Chemistry
3. Adam Mickiewicz University
4. 61-614 Poznan, Poland
5. Institute of Low Temperature and Structure Research
6. Polish Academy of Sciences
7. 50-950 Wroclaw, Poland
8. Institute of Physics
9. University of Tartu
10. 51014 Tartu, Estonia
11. Photon Science Division at DESY
12. D-22607 Hamburg, Germany