[1] Nanyang Inst Technol, Sch Civil Engn, Nanyang, Peoples R China
[2] HITECH Univ, Dept Math, Taxila, Punjab, Pakistan
[3] King Khalid Univ, Coll Sci, Dept Math, Abha 61413, Saudi Arabia
[4] Univ Tabuk, Univ Coll Duba, Dept Math, Tabuk, Saudi Arabia
[5] Gomal Univ, Inst Numer Sci, Dept Math, Dera Ismail Khan, Kpk, Pakistan