1. B. A. Boyko, A. I. Bykov, M. I. Dolotenko, et al., in Book of Abstracts of the VIII International Conference on Megagauss Magnetic Field Generation and Related Topics, Tallahassee, USA, p. 149.
2. P. G. Harper, Proc. Phys. Soc. London, Sect. A 68, 874 (1955).
3. G. E. Zil’berman, Zh. Éksp. Teor. Fiz. 32, 296 (1957) [Sov. Phys. JETP 5, 208 (1957)]; Zh. Éksp. Teor. Fiz. 34, 515 (1958) [Sov. Phys. JETP 7, 355 (1958)].
4. M. Ya. Azbel’, Zh. Éksp. Teor. Fiz. 46, 929 (1964) [Sov. Phys. JETP 19, 634 (1964)].
5. D. R. Hofstadter, Phys. Rev. B 14, 2239 (1976).