1. Tsendin, L.D., Zh. Eksp. Teor. Fiz., 1974, vol. 66,issue 5, p. 1638.
2. Tsendin, L.D., Zh. Tekh. Fiz., 1982, vol. 52,issue 4, p. 635.
3. Tsendin, L.D., Plasma Sources Sci. Technol., 1995, vol. 4, no. 2, p. 200.
4. Golubovskii, Yu.B. and Porokhova, I.A., Opt. Spektrosk., 1999, vol. 86, no. 6, p. 960 (Opt. Spectrosc. (Engl. transl.), vol. 86, no. 6).
5. Golubovskii, Yu.B., Nekuchaev, V.O., Ponomarev, N.S., and Porokhova, I.A., Zh. Tekh. Fiz., 1997, vol. 67, no. 9, p. 14.