1. Department of Natural Sciences, Faculty of Hotel Management and Tourism, University of Kragujevac, 36210 Vrnjačka Banja, Serbia
2. Faculty of Business and Law, University “MB”, 11000 Belgrade, Serbia
3. Academy of Technical and Art Applied Studies, 11000 Belgrade, Serbia
4. Mathematics Division, School of Advanced Sciences and Languages, VIT Bhopal University, Bhopal-Indore Highway, Sehore 466114, Madhya Pradesh, India
5. Department of Mathematics, Pandit Deendayal Upadhyaya Adarsha Mahavidyalaya, Amjonga, Goalpara 783124, Assam, India
6. Department of Mathematics, Gilan-E-Gharb Branch, Islamic Azad University, Gilan-E-Gharb 6787141343, Iran