1. F. M. Ernsberger, Glass Ind. 47 (1966) 481.
2. T. J. Ahrens and S. Katz, J. Geophys. Res. 67 (1962) 2935.
3. Timoshenko, ?Theory of Plates and Shells? (McGraw-Hill, 1940), p. 70.
4. D. B. Binns, ?Science of Ceramics?, Vol. 1 (Academic Press, 1962), p. 315.
5. J. Selsing, J. Amer. Ceram. Soc. 44 (1961) 419.