1. V. Efimov, Influence of Resonance in Pair Forces on the Spectra of Three-Particle Levels, MIPhI, Moscow (1973).
2. T. Andras, Resonances in Few-Body Systems, Springer, New York (2002).
3. A. Poincare, Selected Works, Nauka, Moscow (1971-1972), Vols. 1, 2.
4. G. J. Schultz, Rev. Mod. Phys., 45, 423 (1973).
5. G. F. Drukarev, Collisions of Electrons with Atoms and Molecules, Plenum, New York (1987).