REFERENCES
- P. Levesque and L. Gerlach, J. Amer. Ceram. Soc., 1956, 39, 119.
- Private communication from H. Rawson, B.T.H. Research Laboratories.
- V. J. Haddrell, E. C. Sykes, and B. W. Mott, J. Inst. Metals, 1955-56, 84, 112.
- E. W. Roberts, Trans. Brit. Ceram. Soc., 1955, 54, 120, 126.