“…Besides, qualitative properties of solutions of third order differential equations such as stability, instability, boundedness, oscillation, and periodicity of solutions have been studied by many authors; in this regard, we refer the reader to the monograph by Reissig et al [17], and the recent papers of Adams et al [1], Ademola and Arawomo [2], Afuwape and Adesina [3], Bai and Guo [5], Ogundare and Okecha [15], Rauch [16], Sadek [18], Tunç ([20]- [27]), Zhang and Yu [29] and the references cited therein. However, to the best of our knowledge, there exist few results on the mentioned qualitative behaviors of solutions for the non-autonomous third order differential equations of retarded type (see, the references of this paper).…”