Authors
Amar Belacel
University of Laghouat, Laboratoire de Mathématiques Pures et Appliques, Laghouat, Algeria
Khedidja Bey
University of Laghouat, Laboratoire de Mathématiques Pures et Appliques, Laghouat, Algeria
© 2019 Amar Belacel, Khedidja Bey, published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.