1. Ewald, P. P., Z. Krist., 56, 129 (1921).
2. Runge, C., Phys. Z., 18, 509 (1917).
3. Niggli, P., “Handb. d. exper. Phys.", VII, 1, 108 (1929).
4. Delaunay, B., Z. Krist., 84, 131 (1933). See also Brandenberger, E., “Angewandte Kristallstrukturlehre", 153 (Berlin, 1938).
5. For example, Buerger, M. J., Amer. Min., 22, 418 (1937). Bernal, J. D., Proc. Roy. Soc., 113, 117 (1926).