1. Z. Yang, M. Fleck, M. Smith, et al., Europ. J. Mineral. 14, 969 (2002).
2. P. M. Kartashov, A. V. Voloshin, and Yu. A. Pokhomovsky, Zap. Vseross, Mineral. Ob-va 122(3), 65 (1993).
3. A. P. Kalita, Tr. IMGRE, Issue 16, 107 (1963).
4. V. I. Fin’ko, Izv. AN SSSR, Ser. Geol., No. 11, 90 (1964).
5. J. Van Velthuizen and G. Chao, Canad. Mineral. 27, 125 (1989).