1. L. D. Faddeev and L. A. Takhtajan, Hamiltonian Methods in the Theory of Solitons (Nauka, Moscow, 1986; Springer, Berlin, 1990).
2. Ia. G. Sinai, Theory of Dynamical Systems. Part I. Ergotic Theory (Warsaw Univ. Press, Warsaw, 1969).
3. D. Balianu and N. Makhaldiani, JINR Commun. No. E2-98-348 (Joint Institute for Nuclear Research, Dubna, 1998); solv-int/9903002; Roumanian J. Phys. 44, Nos. 9–10 (1999).
4. Y. Nambu, Phys. Rev. D 7, 2405 (1973).
5. N. Makhaldiani, JINR Commun. No. E2-97-407 (Joint Institute for Nuclear Research, Dubna, 1997); solv-int/9804002.