1. V. V. Suran and I. P. Zapesochnyi, Pis’ma Zh. Tekh. Fiz. 1, 973 (1975) [Sov. Tech. Phys. Lett. 1, 420 (1975)].
2. I. S. Aleksakhin, N. B. Delone, I. P. Zapesochnyi, and V. V. Suran, Zh. Éksp. Teor. Fiz. 76, 887 (1979) [Sov. Phys. JETP 49, 447 (1979)].
3. I. I. Bondar’, N. B. Delone, I. P. Zapesochnyi, and V. V. Suran, Pis’ma Zh. Tekh. Fiz. 7, 243 (1981) [Sov. Tech. Phys. Lett. 7, 104 (1981)].
4. D. Feldmann, H. J. Krautwald, and K. H. Welge, J. Phys. B 15, L529 (1982).
5. P. Camus, M. Kompitsas, S. Cohen, et al., J. Phys. B 22, 445 (1989).