1. Yu. M. Kiselev, Zh. Neorg. Khim. 39(8), 1266 (1994).
2. G. A. Bandurkin, B. F. Dzhurinskii, and I. V. Tananaev, Crystal-Chemical Features of Rare-Earth Compounds (Nauka, Moscow, 1984) [in Russian].
3. V. A. Blatov, A. P. Shevchenko, and V. N. Serezhkin, Koord. Khim. 25(7), 483 (1999) [Russ. J. Coord. Chem. 25 (7), 453 (1999)].
4. Inorganic Crystal Structure Database (FIZ Karlsruhe & NIST Gaithersburg, 2004).
5. Cambridge Structural Database System. November 2004 Release.