“…Besides, the CH equation has a reciprocal link to the first negative flow of the KdV hierarchy [7], and the conservation laws of each may be connected [8]. Subsequently, many other CH type equations (the equations possess peakon solutions) are proposed and studied, such as the DP equation, the Novikov's equation and the Geng-xue equation [9,10,11,12,13,14,15]. Although many of them is integrable but it has some nonstandard features such as the weak Painlevé property, and is still much to understand via reciprocal transformation [16].…”