1. Radiation Physics Laboratory, Department of Physics, Faculty of Sciences, Badji Mokhtar University P.O. Box 12, 23000 Annaba, Algeria
2. School of Mathematics, Centre for Differential Equations Continuum Mechanics and Applications University of the Witwatersrand, Johannesburg, Wits 2050, South Africa
3. Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
4. Department of Mathematics, Faculty of Science, Beni-Suef University, Beni-Suef, Egypt
5. Department of Mathematical Sciences, Delaware State University, Dover, DE 19901-2277, USA