1. Institute of Nuclear Sciences “Vinča”, P. O. Box 522, 11001 Belgrade, Yugoslavia
2. Institute of Chemistry, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovica 3, 21000, Novi Sad, Yugoslavia
3. Department of Chemistry, University of Belgrade, Studentski trg 16, P. O. Box 158, 11001 Belgrade, Yugoslavia, Fax:(internat.) + 381‐11/638‐785
4. Department of Biology, Chemistry and Pharmacy, Institute of Chemistry, Free University of Berlin, Takustrasse 6, 14195 Berlin, Germany