[1] P. Boiti, J. J. P. Leon, M. Manna and F. Pempinelli, Inverse
Probl. 3 (1987), 1205.
[2] S. Y. Lou, Phys. Lett. A 176 (1993), 9.
[3] S. Y. Lou, Math. Meth. Appl. Sci. 18 (1995), 789.
[4] G. Paquin and P. Winternitz, Physica D 46 (1990), 122.
[5] Li-Na Song et al., Chaos Solitons Fractals 31 (2007), 548-556.
[6] X. Y. Tang, C. L. Chen and S. Y. Lou, J. Phys. A 35 (2002),
L293.
[7] X. Y. Tang and S. Y. Lou, Chaos Solitons Fractals 14 (2002),
1451.
[8] A. M. Wazwaz, New solitary wave solutions to the modified forms of
Degasperis-Procesi and Camassa-Holm equations, Appl. Math. Comput.
186(1) (2007), 130-141.