1. Department of Mathematics, College of Science, University of Baghdad, Baghdad 10071, Iraq
2. Ministry of Education, Al-Rusafa 2, Baghdad 10082, Iraq
3. Department of Mathematics, College of Sciences, University of Sharjah, Sharjah 27272, United Arab Emirates
4. Department of Mathematics and Computer Science, University of Oradea, 1 Universitatii Street, 410087 Oradea, Romania