“…In recent years, research on homoclinic and heteroclinic orbits in dynamical systems has attracted much attention [Ren & Li, 2010;Lv & Tang, 2013;Chen, 2013;Li et al, 2013;Costa & Tehrani, 2014;Balasuriya & Padberg-Gehle, 2014;Lima & Teixeira, 2013;Zhou et al, 2004;Wang et al, 2007;EI-Dessoky et al, 2012;Zheng & Chen, 2006]. The study about the homoclinic and heteroclinic orbits in second-order differential systems has received major development [Lv & Tang, 2013;Chen, 2013;Li et al, 2013;Costa & Tehrani, 2014;Balasuriya & Padberg-Gehle, 2014;Lima & Teixeira, 2013]. Reference [Zhou et al, 2004] determined the homoclinic and heteroclinic orbits in the Chen system by using the undetermined coefficient method, which was also applied to the Lorenz-family system [Wang et al, 2007], Lü system, Zhou's system [EI-Dessoky et al, 2012], a class of 3D quadratic autonomous chaotic systems [Zheng & Chen, 2006] and the Chen system with time-delays [Ren & Li, 2010].…”