1. B. F. Kononkov and A. B. Sapozhnikov, Proceedings of the Radio Day Scientific-Technical Conference [in Russian], Tomskogo Universiteta (1964), p. 161.
2. W. Steidinger, Arch. fur El,23, 153 (1928).
3. B. F. Kononkov and A. B. Sapozhnikov, Izvestiya VUZ. Fizika, No. 4, 70 (1963).