Authors
Athmane Boumazourh
Department of Mathematics, Sidi Mohamed Ben Abdellah University, Fez, Morocco
Mohammed Srati
Department of Mathematics, Sidi Mohamed Ben Abdellah University, Fez, Morocco
© 2020 Athmane Boumazourh, Mohammed Srati, published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.