Authors
Abdelkebir Saad
Department of Mathematics, University of M’sila, Algeria
Nouiri Brahim
Laboratory of Pure and Applied Mathematics, University of M’sila, Algeria
© 2021 Abdelkebir Saad, Nouiri Brahim, published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.