“…Compared with the numerical investigation reported in [Rabinovich & Fabrikant(1979)], the studies in [Danca & Chen(2004)] (and also in [Luo et al(2007)]), revealed some new interesting aspects. Since then, the interest in this system, has continuously increased, partially following the direction of [Danca & Chen(2004)] (see [Chairez(2014), Azzaz et al(2013), Serrano-Guerrero et al(2013), Motsa et al(2012), Zhang et al(2011), Srivastava et al(2014), Umoh & Edwin(2013), Agrawal et al(2012)], utilizing some computer software such as Matlab Central [Moysis(2014)] or Wolfram [Craven(1011)]).…”