1. N. S. Shiren, Phys. Rev. B, 2, 2471–2487 (1970); G. A. Denisenko, JETP, 33, 1220 (1971); V. V. Samartsev, B. P. Smolyakov, and R. Z. Sharipov, JETP Lett., 20, 296–297 (1974).
2. S. A. Ahmanov, V. A. Vyslouh, and A. S. Cirkin, Optics of Femtosecond Laser Pulses [in Russian], Nauka, Moscow (1988); V. E. Gusev and N. B. Karabutov, Laser Optoacoustics [in Russian], Nauka, Moscow (1991); S. A. Ahmanov and V. É. Gusev, Sov. Phys. Usp., 35, No. 3, 153–191 (1992).
3. S. L. McCall and E. L. Hahn, Phys. Rev. Lett., 18, 908–911 (1967).
4. V. E. Zaharov, S. V. Manakov, S. P. Novikov, and L. P. Pitaevskii, Theory of Solitons: The Inverse Scattering Method [in Russian], Nauka, Moscow (1980); English transl., Plenum, New York (1984); G. L. Lamb Jr., Elements of Soliton Theory, Wiley, New York (1980).
5. L. D. Faddeev and L. A. Takhtadzhyan, The Hamiltonian Methods in the Theory of Solitons [in Russian], Nauka, Moscow (1986); English transl., Springer, Berlin (1987).