1. Deer, W. A., Howie, R. A., and Zussmann, J., Rock-Forming Minerals, Vols 1–5 (Wiley, New York, 1962).
2. Barrer, R. M., and Marshall, D. J., J. Chem. Soc., 6616–6621 (1965).
3. McConnell, D., Am. Miner., 37, 609–617 (1952).
4. Deer, W. A., Howie, R. A., and Zussmann, J., Rock-Forming Minerals, 1, 213 (Wiley, New York, 1962).
5. McConnell, D., Am. Miner., 22, 977–986 (1937).