1. Sodomka L., Phys.Stat.Sol. A 7 (1971), K 65.
2. Sodomka L., Kleprlík A., JMO 18 (1973), 16, 71.
3. Sodomka I., Petr J., Proc.of Conf.Czech.Phys., Liberec, Academia, Praha, p.651.
4. The measurement was carried out on the experimental arrangement prepared by I.Cabák, UP Olomouc.
5. Henisch H.K., Electroluminescence. Pergamon Press, 1962, p.192.