1. Department of Pure and Applied Mathematics, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
2. Department of Mathematics, Vaal University of Technology, Vanderbijlpark, South Africa
3. Department of Mathematics, University of Kansas, Lawrence, USA
4. Department of Mathematical Sciences, Redeemer's University, Ede, Nigeria
5. Department of Education, Vaal University of Technology, Vanderbijlpark, South Africa