1. Department of Mathematics, Rheinland-Pfälzische Technische Universität (RPTU), 67663 Kaiserslautern, Germany
2. Faculty of Science, Mathematics Department, Kahramanmaras Sutcu Imam University, 46050 Kahramanmaras, Turkey
3. Institute of Financial Mathematics and Applied Number Theory, Johannes Kepler University (JKU) Linz, 4040 Linz, Austria