1. S. Burgsetöl, B. B. Jensen, and H. Neumann, Lithos 10, 81 (1977).
2. R. V. Gaines, H. C. W. Skinner, E. E. Foord, et al., Dana’s New Mineralogy: The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana (Wiley, New York, 1997).
3. D. J. M. Bevan, J. Strohle, and O. Greis, J. Solid State Chem. 44, 75 (1982).
4. IPDS: Imaging Plate Diffraction System, Version 2.90 (STOE and CIE, Darmstadt, Germany, 1999).
5. G. M. Sheldrick, SHELXS97: Program for the Solution of Crystal Structures (University of Göttingen, Göttingen, Germany, 1997).