1. Goldman, D.S., Rossman, G.R.: Am. Mineral. 63 (1978) 490
2. Cerny, P., Hawthorne, F.C., Jarosewich, E.: Can. Mineral. 18 (1980) 41
3. Hemingway, B.S., Robie, R.A., Kittrick, J.A., Grew, E.S., Nelen, J.A., London, D.: Am. Mineral. 69 (1984) 701
4. Armbruster, Th.: Eur. J. Mineral. 1 (1989) 715
5. Bruckmann, P., Chatterjee, N.D., Rammensee, W., Bielefeld, K.: Phys. Chem. Miner. 20 (1993) 362