1. VSB-Technical University of Ostrava, 17. Listopadu 15/2172, Ostrava 708 33, Czech Republic
2. Center for Basic and Applied Research, Faculty of Informatics and Management, University of Hradec Kralove, Rokitanskeho 62, Hradec Kralove 500 03, Czech Republic
3. Department of Geology, Faculty of Space and Environmental Science, University of Trier, Trier, Germany
4. Adekunle Ajasin University, Akungba-Akoko, Nigeria