Author(s):
1. Risto Popovski, University Goce Delcev, Macedonia
2. Lazo Pekevski, Seiz,ological observatory, Skopje, Macedonia
3. Zoran Panov, University of Goce Delcev, Faculty of natural and technical sciences, Macedonia
4. Blagica Doneva, University of Goce Delcev, Faculty of natural and technical sciences, Macedonia
5. Zivko Gocev, Rudnik , Macedonia

Final paper