“…Fractional calculus is a highly valuable tool in the modeling of many sorts of scientific phenomena in various fields of science, engineering and physics [5,25,26]. Recently, many articles have investigated some aspects of differential equations with fractional-order derivatives, especially the existence, the uniqueness the methods for explicit and numerical solutions and the stability of solutions, we refer to [6,8,9,15,16,23,24] and the references cited therein. In recent years, oscillatory behaviour of fractional differential equations has been investigated by authors, see papers [2-4, 7, 10, 12, 14, 17-19, 27].…”