[1] Lodz Univ Technol, Dept Automat Biomech & Mechatron, 1-15 Stefanowskiego St, PL-90924 Lodz, Poland
[2] Govt Coll Univ, Dept Math, Lahore 54000, Pakistan
[3] Univ Management & Technol, Dept Math, Lahore 54770, Pakistan
[4] Univ Free State, Inst Groundwater Studies, Bloemfontein, South Africa