[1] Univ Gujrat, Dept Math, Gujrat 50700, Pakistan
[2] Quaid I Azam Univ, Dept Math, Islamabad 44000, Pakistan
[3] Univ Chinese Acad Sci, Chinese Acad Sci, Sch Math Sci, Acad Math & Syst Sci,LSEC, Beijing 100190, Peoples R China
[4] Univ Chinese Acad Sci, Chinese Acad Sci, Sch Math Sci, Acad Math & Syst Sci,ICMSEC, Beijing 100190, Peoples R China
[5] Al Farabi Kazakh Natl Univ, Dept Math & Comp Modeling, Alma Ata, Kazakhstan
[6] Kazakh British Tech Univ, Dept Math & Comp Modeling, Alma Ata, Kazakhstan