[1] Hunan Univ, Sch Math, Changsha, Peoples R China
[2] Riphah Int Univ I 14, Dept Math & Stat, Islamabad, Pakistan
[3] Peking Univ, Dept Mech & Engn Sci, Beijing, Peoples R China
[4] Prince Sattam Bin Abdulaziz Univ, Coll Sci & Humanities Al Kharj, Dept Math, Al Kharj, Saudi Arabia
[5] Menoufia Univ, Fac Engn, Dept Basic Engn Sci, Shibin Al Kawm, Egypt
[6] Princess Nourah Bint Abdulrahman Univ, Coll Sci, Dept Phys, Riyadh, Saudi Arabia
[7] Quaid I Azam Univ, Dept Math, Islamabad, Pakistan
[8] Taif Univ, Coll Sci, Dept Math & Stat, At Taif, Saudi Arabia