1. Department of Mathematical Science, College of Science, Princess Nourah Bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia
2. Section of Mathematics, International Telematic University Uninettuno, CorsoVittorio Emanuele II, 39, 00186 Roma, Italy
3. Department of Mathematics, Faculty of Science, Mansoura University, Mansoura 35516, Egypt
4. Department of Mathematics and Computer Science, University of Oradea, 1 University Street, 410087 Oradea, Romania