1. Rimkevich, V.S., Malovitskii, Yu.N., and Demyanova, L.P., RF Patent 2286947, 2006.
2. Demyanova, L.P. and Zaeva, A.S., Ratio of starting raw material and fluorinating agent in the process of purifying silica-containing raw material, Theor. Found. Chem., Eng., 2012, vol. 46, p. 368.
3. Khimicheskaya entsiklopediya (Encyclopedia of Chemistry), Moscow Sovetskaya Entsiklopediya, 1990, vol. 2.
4. Rakov, E.G., Fluoride metallurgy, Izv. Vyssh. Uchebn. Zaved., Khim. Khim. Tekhnol., 1987, vol. 3, no. 4, p. 3.
5. Rakov, E.G. and Mel’nichenko, E.I., Properties and reactions of ammonium fluorides, Usp. Khim., 1984, vol. 53, no. 9, p. 1463.