1. Dep. of Chemistry; Norwegian Univ. of Science and Technology; NO-7491 Trondheim Norway
2. Dep. of Chemistry; Univ. of Montreal; C.P. 6128 Succursale Centre-Ville Montréal QC Canada H3C 3J7
3. Dep. of Ecology and Environmental Science; Umeå Univ.; S-901 83 Umeå Sweden