[1] Ghazi Univ, Dept Math, DG Khan, Pakistan
[2] Univ Lahore, Dept Math & Stat, Lahore 54590, Pakistan
[3] Biruni Univ, Dept Comp Engn, Istanbul, Turkey
[4] Firat Univ, Sci Fac, Dept Math, Elazig, Turkey
[5] China Med Univ, Dept Med Res, Taichung, Taiwan
[6] Univ Cheikh Anta Diop Dakar, Dept Math Decis, Lab Lmdan, Fac Sci Econ & Gest, BP 5683, Dakar, Senegal