1. Department of Mathematics, University of the Punjab, Quaid-e-Azam Campus, Lahore, Pakistan
2. Department of Mathematics and Science Education, Faculty of Education, Harran University, Sanliurfa, Turkey
3. Departamento de Matematica Aplicada y Estadistica, Universidad Politecnica de Cartagena, Hospital de Marina, 30203 Cartagena, Region de Murcia, Spain