1. V. N. Borisko and A. A. Petrushenya, Zh. Tekh. Fiz. 73(1), 86 (2003) [Tech. Phys. 48, 80 (2003)].
2. N. A. Kervalishvili, Fiz. Plazmy 15, 359 (1989) [Sov. J. Plasma Phys. 15, 211 (1989)].
3. N. A. Kervalishvili, Fiz. Plazmy 15, 753 (1989) [Sov. J. Plasma Phys. 15, 436 (1989)].
4. N. A. Kervalishvili, Zh. Tekh. Fiz. 60(2), 78 (1990) [Sov. Phys. Tech. Phys. 35, 182 (1990)].
5. E. H. Hirsh, Br. J. Appl. Phys. 15, 909 (1964).