1. P. M. Moore and T. Araki, Neues Jahrb. Mineral. Abh. 132, 231 (1978).
2. G. Ferraris, G. Ivaldi, and C. Chopin, Eur. J. Mineral. 7, 167 (1995).
3. B. F. Hoskins, W. G. Mumme, and M. W. Pryce, Mineral. Mag. 53, 457 (1989).
4. S. S. Kazantsev, D. Yu. Pushcharovskiĭ, M. Pazero, et al., Kristallografiya 50(1), 49 (2005) [Crystallogr. Rep. 50, 42 (2005)].
5. N. V. Zubkova, D. Yu. Pushcharovskiĭ, Yu. K. Kabalov, et al., Kristallografiya 51(1), 23 (2006) [Crystallogr. Rep. 51, 16 (2006)].