1. [1] R. D. Shannon, C. T. Prewitt, Acta Cryst, B25, 925 (1969).
2. [2] R. D. Shannon, Acta Cryst, A32, 751 (1976).
3. [3] The Chemical Society of Japan, ed., Handbook of Chemistry: Pure Chemistry, 2nd-5th eds., Maruzen Pub. Tokyo (until 2004).
4. [4] L. Pauling, J. Am. Chem. Soc., 49, 765 (1927).
5. [5] L. Pauling, J. Am. Chem. Soc., 51, 1010 (1929).