1. Kostov, I., Mineralogy, Edinburgh: Oliver and Boyd, 1968.
2. Zakharenko, V.S. and Parmon, V.N., Russ. J. Phys. Chem., 1999, vol. 73, no. 1, p. 117.
3. Lisachenko, A.A. and Vilesov, F.I., Usp. Foton., 1974, no. 4, p. 18.
4. Volodin, A.M., Khim. Fiz., 1992, vol. 11, no. 8, p. 1054.
5. Zakharenko, V.S., Catal. Today, 1997, vol. 39, no. 3, p. 243.