1. Department of Mathematics, Ramanujan School of Mathematical Sciences, Pondicherry University, Puducherry 605014, India
2. Institute of Applied Mathematics, John von Neumann Faculty of Informatics, Óbuda University, 1034 Budapest, Hungary
3. Faculty of Maritime Studies, University of Rijeka, 51000 Rijeka, Croatia
4. Faculty of Technical Sciences, University of Novi Sad, 21000 Novi Sad, Serbia