Authors
Marija Paunovic
Department of Natural Science, University of Kragujevac, Faculty of Hotel Management and Tourism, Department of Computer Science, University MB, Faculty of Business and Law, Vrnjacka Banja
Babak Mohammadi
Department of Mathematics, Marand Branch, Islamic Azad University, Marand, Iran
Vahid Parvaneh
Department of Mathematics, Gilan-E-Gharb Branch, Islamic Azad University, Gilan-E-Gharb, Iran