1. L. D. Landau and E. M. Lifshitz, Quantum Mechanics: Non-Relativistic Theory (Nauka, Moscow, 1989, 4th ed.; Pergamon Press, Oxford, 1977, 3rd ed.).
2. A. S. Davydov, Quantum Mechanics, 2nd ed. (Nauka, Moscow, 1973; Pergamon Press, Oxford, 1976).
3. P. A. Braun and A. A. Kiselev, Introduction to the Theory of Molecular Spectra (Leningr. Gos. Univ., Leningrad, 1983) [in Russian].
4. A. V. Burenin, Usp. Fiz. Nauk 176, 847 (2006).
5. A. V. Burenin, Symmetry of Quantum Intramolecular Dynamics (IPF RAN, Novgorod, 2006) [in Russian].