1. M. Toda, ?Waves in nonlinear lattice,? Progr. Theor. Phys. Suppl.,45, 174?200 (1970).
2. V. E. Zakharov and A. V. Mikhailov, ?Relativistically invariant two-dimensional models of field theory which are integrable by means of the inverse scattering problem method,? Zh. Eksp. Teor. Fiz.,74, No. 6, 1953?1973 (1978).
3. S. V. Manakov, ?Nonlinear Fraunhofer diffraction,? Zh. Eksp. Teor. Fiz.,65, No. 4, 1392?1398 (1973); ?Complete integrability and stochastization of discrete dynamical systems,? Zh. Eksp. Teor. Fiz.,67, No. 2, 543?555 (1974).
4. H. Flaschka, ?On the Toda lattice. II,? Progr. Theor. Phys.,51, No. 3, 703?716 (1974).
5. S. V. Manakov, Dissertation, Inst. Teor. Fiz. im. L. D. Landau (1974).