Authors
Malika Boutiba
Mathematics Department, Djillali Liabes University of Sidi Bel-Abbes, Sidi Bel-Abbes, Algeria
Mathematics Department, Djillali Liabes University of Sidi Bel-Abbes, Sidi Bel-Abbes, Algeria
Michal Fečkan
Department of Mathematical Analysis and Numerical Mathematics, Comenius University in Bratislava, Bratislava, Slovakia