“…The study of the existence of oscillatory and periodic solutions is one of the most interesting topics for applications. The oscillatory and periodic solutions with deviating arguments has been the subject of many investigations; see, for instance, [1,2,6,7,10,12,14,16,18,21,22,[30][31][32]34] and the references cited therein. Of particular importance, however, has been the study of oscillatory and periodic solutions which are caused by the argument deviations and which do not appear in the corresponding ordinary differential equations; see [23].…”