1. Department of Mathematics, College of Science, University of Ha’il, P.O.~Box 2440, Ha’il 81451, Saudi Arabia
2. Department of Mathematics, Faculty of Science, Mansoura University, Mansoura 35516, Egypt
3. Department of Mathematical Science, College of Science, Princess Nourah Bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia
4. Section of Mathematics, International Telematic University Uninettuno, Corso Vittorio Emanuele II, 39, 00186 Roma, Italy