1. Université de Poitiers, Laboratoire de Mathématiques et Applications, Chasseneuil Futuroscope Cedex, Chasseneuil-du-Poitou, France
2. Lebanese University, Khawarizmi Laboratory for Mathematics and Applications, Beirut, Mont Liban, Lebanon
3. Department of Mathematics and Physics, Lebanese International University, West Bekaa, Lebanon
4. School of Mathematical Sciences, Xiamen University, Fujian Provincial Key Laboratory of Mathematical Modeling and High Performance Scientific Computing, Xiamen, Fujian, People's Republic of China