1. E. V. Suvorov and A. A. Fraiman, Fiz. Plazmy 6, 1161 (1980) [Sov. J. Plasma Phys. 6, 639 (1980)].
2. A. G. Zhukovskii, Fluctuations of Plasma Density (Énergoatomizdat, Moscow, 1993).
3. B. van Milligen, E. Sánchez, T. Estrada, et al., Plasma Phys. 2, 3017 (1996).
4. A. N. Malakhov, Fluctuations in Self-Oscillation Systems (Nauka, Moscow, 1968).
5. M. I. Rabinovich and D. I. Trubetskov, Introduction to the Theory of Oscillations and Waves (Nauka, Moscow, 1984), Sec. 16.1.