1. Department of Applied Mathematics, Faculty of Mathematical Sciences, Shahrekord University, Shahrekord, Islamic Republic of Iran
2. School of Mathematical Sciences, Nanjing Normal University, Nanjing, People's Republic of China
3. Institute of Engineering, Polytechnic of Porto, Department of Electrical Engineering, R. Dr. António Bernardino de Almeida, Portugal
4. Department of Mathematics, Yasouj University, Yasouj, Islamic Republic of Iran