1. I. I. Mazur and O. P. Ivanov, Dangerous Natural Processes (Ekonomika, Moscow, 2004) [in Russian].
2. S. A. Pulinets, V. V. Khegai, K. A. Boyarchuk, and A. M. Lomonosov, Phys. Usp. 41, 515 (1998).
3. R. Reiter, Phenomena in Atmospheric and Environmental Electricity (Elsevier, Amsterdam, London, New York, 1992).
4. A. I. Grigor’ev, N. I. Gershenzon, and N. G. Gokhberg, Dokl. Akad. Nauk 300, 1087 (1988).
5. Y.-S. Zou, Phys. Scr. 52, 726 (1995).