1. B. P. Sobolev, The Rare Earth Trifluorides, Part 2: Introduction to Materials Science of Multicomponent Metal Fluoride Crystals (Institute of Crystallography, Moscow, 2001; Institut d’Estudis Catalans, Barcelona, 2001).
2. A. de Kozak, M. Samuel, and A. Chretien, Rev. Chim. Miner. 8(6), 805 (1971).
3. I. I. Buchinskaya and P. P. Fedorov, Kristallografiya 49(2), 334 (2004) [Crystallogr. Rep. (Engl. Transl.) 49 (2), 279 (2004)].
4. R. H. Nafziger, J. Am. Ceram. Soc. 54(9), 467 (1971).
5. D. Klimm, M. Rabe, R. Bertram, et al., J. Cryst. Growth 310(1), 152 (2008).