1. Solitons, Nonlinear Evolution Equations and Inverse Scattering;Ablowitz,1991
2. Solitons and the Inverse Scattering Transform;Ablowitz,1981
3. On billiard solutions of nonlinear PDEs;Alber;Phys. Lett. A,1999
4. The complex geometry of weak piecewise smooth solutions of integrable nonlinear PDE׳s of shallow water and Dym type;Alber;Comm. Math. Phys.,2001
5. Alber M.S., Camassa, R., Gekhtman, M., 2000. On billiard weak solutions of nonlinear PDE׳s and Toda flows. In: CRM Proceedings and Lecture Notes 25, pp. 1–11.