Comments on “Some conditions on zeros to avoid step responseextrema”. I

摘要

This paper comments the results of the above-mentioned paper by Rachid (ibid., vol.40, p.1501-3 (1995)) and points out that the sufficient condition given has already been previously included in papers by Jayasuriya-Franchek (1991), Jayasuriya-Song (1992) and Song (1992) as a special case