Zsolt  Lipcsey, I.O.  Isaac, 
    Oscillations in Non-Autonomous Neutral Impulsive Differential Equations with Several Delays,
    Journal of Modern Mathematics and Statistics,
    Volume 3,Issue 4,
    2009,
    Pages 73-77,
    ISSN 1994-5388,
    jmmstat.2009.73.77,
    (https://makhillpublications.co/view-article.php?doi=jmmstat.2009.73.77)
    Abstract: In this study, we establish some sufficient conditions 
        for the oscillation of all the solutions of the non-autonomous neutral 
        impulsive differential equation with several delays </P>
      <table width="100%" border="0">
        <tr>
          <td height="90"> 
            <div align="center"><img src="http://medwelljournals.com/fulltext/jmmstat/2009/images/image1-2k9-73-77.gif" width="388" height="106"></div></td>
        </tr>
      </table>
      <P>where, t, t<SUB>k</SUB>&ge;t<SUB>0</SUB>. The study was carried out under 
        the assumption that for sufficiently large t, the coefficients of the 
        equation satisfy the conditions </P>
      <table width="100%" border="0">
        <tr> 
          <td><div align="center"><img src="http://medwelljournals.com/fulltext/jmmstat/2009/images/image2-2k9-73-77.gif" width="352" height="42"></div></td>
        </tr>
      </table>
    Keywords: dependence of conditions on coefficients and delays;sufficient oscillatory conditions;Non-autonomous neutral impulsive equations;characteristic equation;characteristic roots