1. Department of Basic Sciences and Humanities, College of Computer and Information Sciences, Majmaah University, Al Majmaah 11952, Saudi Arabia
2. Department of Mathematics, Government College University, Faisalabad 38000, Pakistan
3. School of Computing, University of Leeds, Leeds LS2 9JT, UK
4. Department of Mathematics and Statistics, University of Victoria, Victoria, BC V8P 5C2, Canada