1. Moissan, A., and Stock, A., C.R. Acad. Sci., Paris, 131, 139 (1900).
2. Tone, F., Indust. Eng. Chem., Ind. Ed., 30, 252 (1938).
3. Brewer, L., Sawyer, D. L., Templeton, D. H., and Dauben, C. H., J. Amer. Ceram. Soc., 173 (1952).
4. Nowotny, H., Dimakopoubou, E., and Kudielka, H., Monatsh. Chem., 88, No. 2, 180 (1957).
5. Samsonov, G. V., and Latysheva, V. P., Doklady Akad. Nauk., S.S.S.R., 105, No. 3, 499 (1955).