[1] COMSATS Univ Islamabad, Dept Math, Islamabad 44000, Pakistan
[2] Taif Univ, Coll Engn, Dept Elect Engn, POB 11099, Taif 21944, Saudi Arabia
[3] Univ Politehn Bucuresti, Dept Appl Math, Bucharest 060042, Romania
[4] Acad Romanian Scientists, 54 Splaiul Independentei, Bucharest 050094, Romania
[5] Univ Politehn Bucuresti, Fundamental Sci Appl Engn Res Ctr SFAI, Bucharest 060042, Romania
[6] King Abdulaziz Univ, Fac Sci, Dept Math, Nonlinear Anal & Appl Math Res Grp, Jeddah 21589, Saudi Arabia
[7] Khon Kaen Univ, Fac Sci, Dept Math, Khon Kaen 40002, Thailand