1. Department of Mathematics, COMSATS Institute of Information Technology, Abbottabad, Pakistan
2. Department of Mathematics, Riphah International University, Islamabad, Pakistan
3. School of Mathematical Sciences, Faculty of Sciences and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
4. Foundation Program, Dhofar University, Salalah, Oman
5. Division of Engineering, Higher Colleges of Technology, P.O. Box 4114, Fujairah, UAE