1. A. V. Moskvin, Cathodoluminescence [in Russian], part I, Gostekhizdat, p. 224, 1948.
2. V. L. Levshin, V. B. Gutan, and E. N. Karzhavina, Opt. i Spektr.,6, 372, 1959.
3. M. I. Tombak and A. M. Gurvich, ZhPS [Journal of Applied Spectroscopy],6, 564, 1966.
4. A. M. Gurvich, V. B. Gutan, and M. I. Tombak, Izv. AN SSSR, ser. fiz.,32, 1, 1968.
5. V. B. Gutan, ZhPS [Journal of Applied Spectroscopy],7, 42, 1967.