1. Department of Mathematics, Sana’a University, Sana’a, Yemen
2. Department of Engineering Mathematics & Physics, Faculty of Engineering & Technology, Future University, Egypt
3. Department of Mathematics, Zagazig University, Zagazig, Egypt
4. Department of Mathematics, Faculty of Science, Zarqa University, Zarqa, Jordan
5. Department of Mathematics, College of Sciences and Humanities in Aflaj, Prince Sattam bin Abdulaziz University, Riyadh, Saudi Arabia