1. Bragg, W. L., undG. B. Brown, Z. Krist.63 (1926), 538.
2. Brown, G. B., undJ. West, Z. Krist.66 (1927), 154.
3. Hanke, K., undJ. Zemann, Naturw.50 (1963), 91.
4. Hanke, K., N. Jb. Miner. Mh.8 (1963), 192.
5. Gibbs, J. V., P. B. Moore undJ. V. Smith, 44th Meeting of the Min. Soc. of America, New York (1963).