1. A. I. Nikishov, Kratkie Soobsheniya po Fizike FIAN 44(10), 17 (2017) [Bulletin of the Lebedev Physics Institute 44, 286 (2017)].
2. A. I. Nikishov, Phys. Part. Nucl. 37, 776 (2006).
3. L. D. Landau and E. M. Lifshits, The Classical Theory of Fields (Pergamon, New York, 1980).
4. A. I. Nikishov, Phys. Part. Nucl. Lett. 6 425 (2009).