1. Department of Chemistry, University of Helsinki, P.O. Box 55, A.I. Virtasen Aukio 1, 00014 Helsinki, Finland
2. Department of Chemistry, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
3. Department of Chemistry, University of Jyvaskyla, P.O. Box 35, 40014 Jyväskylä, Finland