Autori:
1. Risto Dambov, University GoceDelcev, Stip Insitute of Mining, Stip, R. Macedonia, Macedonia
2. Radmila Karanakova Stefanovska, Univerzitet Goce Delčev, Macedonia
3. Slobodan Trajkovic, University of Belgrade, Faculty of Mining and Geology, Serbia
4. Igor Stojceski, University of St.Kliment Ohridski Bitola, Faculty of Economics - Prilep, Macedonia

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