1. I. M. Lifshits, S. A. Gredeskul, and L. A. Pastur, Introduction to the Theory of Disordered Systems (Wiley, New York, 1988).
2. A. P. Dmitriev, Sov. Phys. JETP 68, 132 (1989).
3. D. J. Thouless, Phys. Rev. Lett. 47, 972 (1981).
4. I. P. Zvyagin, JETP Lett. 26, 531 (1977).
5. T. V. Laptyeva, S. V. Denisov, G. V. Osipov, and M. V. Ivanchenko, JETP Lett. 102, 603 (2015).