1. Faculty of Technology and Metallurgy University of Belgrade Karnegijeva 4 11000 Belgrade Serbia
2. Faculty of Technical Sciences University of Priština, Knjaza Miloša 7 38220 Kosovska Mitrovica Serbia
3. Faculty of Sciences, University of Priština-Kosovska Mitrovica Department of Chemistry, 38220 Kosovska Mitrovica, Serbia Lole Ribara 29 38220 Kosovska Mitrovica Serbia
4. Vinča Institute of Nuclear Sciences University of Belgrade P.O. Box 522 Belgrade Serbia