1. Department of Mathematics, National Institute of Technology, Rourkela 769008, India
2. Department of Applied Mathematics, Institute for Groundwater Studies, University of the Free State, Bloemfontein, South Africa
3. Department of Mathematical Sciences, North-West University, Mafikeng Campus, Mmabatho 2735, South Africa
4. Department of Mathematics, Yildiz Technical University, 34220 Istanbul, Turkey
5. Department of Mathematics, Faculty of Art & Sciences, Celal Bayar University, Muradiye Campus, 45047 Manisa, Turkey
6. Department of Mathematics and Institute for Mathematical Research, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia