Yu. D. Tret'yakov, E. A. Goodilin, Russian Chem. Reviews, 69:1 (2000), 1–34
A.M. Abakumov, J. Hadermann, G. Van Tendeloo, R.V. Shpanchenko, P.N. Oleinikov, E.V. Antipov, Journal of Solid State Chemistry, 142:2 (1999), 440