[Nazeer, Mubbashar] Govt Coll Univ, Inst Arts & Sci, Dept Math, Chiniot Campus, Faisalabad 35400, Pakistan.
[Hussain, Farooq] BUITEMS, Dept Math Sci FABS, Quetta 87300, Pakistan.
[Shahzad, Qasiar] Riphah Int Univ, Dept Math, Faisalabad Campus, Faisalabad 38000, Pakistan.
[Khan, M. Ijaz] Riphah Int Univ, Dept Math & Stat, Islamabad 44000, Pakistan.
[Kadry, Seifedine] Beirut Arab Univ, Dept Math & Comp Sci, Beirut, Lebanon.