1. Department of Mathematics, COMSATS Institute of Information Technology, Lahore, Pakistan
2. Department of Mathematics, The Pennsylvania State University, York Campus, York, PA, USA
3. Department of Mathematics & Statistics, FBAS, IIU, Islamabad, Pakistan
4. Institute of Systems Engineering, Macau University of Science and Technology, Taipa, Macau
5. School of Electro-Mechanical Engineering, Xidian University, Xi’an, China