1. B. P. Sobolev, Crystallogr. Rep. 57(3), 434 (2012).
2. B. P. Sobolev, Crystal Growth (Nauka, Moscow, 1990), Vol.18, p. 233 [in Russian].
3. B. P. Sobolev, Crystals: Growth, Structure, Properties (Nauka, Moscow, 1993) [in Russian], p. 167.
4. B. P. Sobolev, Zh. Vses. Khim. O-va im. D. I. Mendeleeva 36(6), 726 (1991).
5. B. P. Sobolev, The Rare Earth Trifluorides, Part 1: The High Temperature Chemistry of Rare Earth Trifluorides (Institute of Crystallography, Moscow, and Institut d’Estudis Catalons, Barcelona, 2000) ( www.books.google.ru/books/rare earth trifluorides ).