Authors
Radouane Azennar
Department of Mathematics, Faculty of Sciences, Ibn Tofaïl University, Morocco
Driss Mentagui
Department of Mathematics, Faculty of Sciences, Ibn Tofaïl University, Morocco
© 2020 Radouane Azennar, Driss Mentagui, published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.