1. A. A. Alybakov, Formation, Structure, and Properties of Complex Impurity and Radiative Centers in Ionic Crystals (Ilim, Bishkek, 2003) [in Russian].
2. M. M. Kidibaev, Radiation-Stimulated Processes in (Li, Na)F:U, Me Crystals (IGU UGTU, Yekaterinburg, 1999) [in Russian].
3. A. N. Cherepanov, V. Yu. Ivanov, T. S. Koroleva, and B. V. Shul’gin, Luminescence of Bulk, Fiber, and Nanosized LiF and NaF Crystals (GOU VPO UGTU-UPI, Yekaterinburg, 2006) [in Russian].
4. V. A. Pustovarov, B. V. Shul’gin, M. Kirm, et al., Opt. Spektrosk. 88(5), 790 (2000) [Opt. Spectrosc. 88, 713 (2000)].
5. D. V. Raĭkov, V. Yu. Ivanov, B. V. Shul’gin, et al., in Radiation-Thermal Effects and Processes in Inorganic Materials: Proc. 3rd Int. Conf. (Izd-vo Tomsk. Politekhn. Univ., Tomsk, 2002), p. 239.