“…Researchers often investigate solutions of such nonlinear PDEs (see for examples [17][18][19][20][21]) to gain more insight into these physical phenomena for further applications. Since the celebrated Korteweg-de Vries (KdV) equation was exactly solved by Gardner et al [13], finding exact solutions of nonlinear PDEs has gradually developed into one of the most important and significant directions and many effective methods have been proposed such as the inverse scattering method [1,61,66,69], Hirota's bilinear method [15], Bäcklund transformation [33], Darboux transformation [31,47,64], Painlevé expansion [46,59,60], homogeneous balance method [44], subsidiary equation method [12,22,67,68], first integral method [4], residual power series method [23], and the exp-function method [14,55,56].…”