1. 1) Busing, W. R., Martin, K. O. & Levy, H. A. (1962) Report ORNL-TM-305. Oak Ridge National Laboratory, Oak Ridge, Tennessee.
2. 3) Deer, W. A., Howie, R. A., & Zussman, J. (1982) Rock-forming Minerals, Orthosilicates. Longmans, London.
3. 5) International Tables for X-ray Crystallography, Vol IV. (1974) The Kynoch Press, Birmingham.