1. Department of Mathematics, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia
2. Department of Mathematics, Atilim University, İncek, 06836 Ankara, Turkey
3. Department of Mathematics, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran
4. Department of Mathematics, Babol Branch, Islamic Azad University, Babol, Iran
5. Payame Noor University, Babol, Iran