1. B. P. Sobolev, The Rare Earth Trifluorides, Part 1: The High Temperature Chemistry of the Rare Earth Trifluorides (Institute of Crystallography, Moscow, 2000; Institut d’Estudis Catalans, Barcelona, 2000).
2. B. P. Sobolev, L. S. Garashina, and V. B. Alexandrov, Proc. 3rd Intern. Congress on Crystal Growth (ICCG-3), Marseille, France, July 5–9, 1971, p. 168.
3. O. Greis and J. M. Haschke, Handbook on the Physics and Chemistry of Rare Earths, Ed. by K. A. Gscheidner and Le Roy Eyring (North-Holland, Amsterdam, 1982), Vol. 5. Ch. 45, p. 387.
4. A. M. Golubev and V. I. Simonov, Sov. Phys. Crystallogr. 31(3), 281 (1986).
5. A. M. Golubev, Koord. Khim. 17(12), 1718 (1991).