1. A. V. Kats, V. M. Kontorovich, S. S. Moiseev, and V. E. Novikov, Preprint No. 42 (Institute of Radioelectronics, Academy of Sciences of the Ukr. SSR, Kharkov, 1974).
2. A. V. Kats, V. M. Kontorovich, S. S. Moiseev, and V. E. Novikov, Pis'ma Zh. Éksp. Teor. Fiz. 21, 13 (1975) [JETP Lett. 21, 5 (1975)]; Zh. Éksp. Teor. Fiz. 71, 177 (1976) [Sov. Phys. JETP 44, 93 (1976)].
3. V. I. Karas', S. S. Moiseev, and V. E. Novikov, Pis'ma Zh. Éksp. Teor. Fiz. 21, 525 (1975) [JETP Lett. 21, 245 (1975)]; V. I. Karas', Pis'ma Zh. Tekh. Fiz. 1 (21), 1020 (1975) [Sov. Tech. Phys. Lett. 1, 438 (1975)].
4. V. I. Karas', S. S. Moiseev, and V. E. Novikov, Zh. Éksp. Teor. Fiz. 71, 1421 (1976) [Sov. Phys. JETP 44, 744 (1976)].
5. E. N. Batrakin, I. I. Zalyubovskii, V. I. Karas', et al., Zh. Éksp. Teor. Fiz. 89, 1098 (1985) [Sov. Phys. JETP 62, 633 (1985)].