1. B. A. Dubrovin, V. B. Matveev, and S. P. Novikov, "Nonlinear equations of Korteweg?de Vries type," Usp. Mat. Nauk,31, No. 1, 55?136 (1976).
2. V. E. Zakharov and A. B. Shabat, "A precise theory of two-dimensional self-focusing and one-dimensional self-simulation of waves in nonlinear media," Zh. Eksp. Teor. Fiz.,61, No. 1, 413?417 (1971).
3. V. E. Zakharov and S. V. Manakov, "On resonance interaction of wave packets in nonlinear media," Pisma Zh. Eksp. Teor. Fiz., 18, No. 7, 413?417 (1973).
4. S. V. Manakov, "A remark on the integration of the Euler equations of the dynamics of an n-dimensional rigid body," Funkts. Anal. Prilozhen.,10, No. 4, 93?94 (1976).
5. A. S. Mishchenko and A. T. Fomenko, "Integrability of the Euler equations on semisimple Lie algebras," Dokl. Akad. Nauk SSSR,231, No. 3, 536?538 (1976).