1. Faculty of Science, Jiangsu University, Zhenjiang, Jiangsu, P. R. China
2. Department of Mathematics, Comsats Institute of Information Technology, Islamabad, Pakistan
3. National Engineering Laboratory for Modern Silk, Soochow University, Suzhou, P. R. China
4. Department of Mathematics, Islamic Azad University, Central Tehran Branch, Tehran, Iran
5. Department of Farm Power and Machinery, Faculty of Agricultural Engineering, Sindh Agriculture University, Sindh, Pakistan