1. S. R. Ovshinsky, Electronics, Aug. 14, p.76 (1959).
2. A. D. Pearson, W. R. Northover, J. F. Dewald, W. F. Peck, Advances in Glass Technology, Eds. F. R. Matson and G. E. Rindone, part I, p. 367, part II, p. 163, Plenum Press, New York 1962 and 1963.
3. B.Y. Kolomiets, E. A. Lebedev, Radiotehnika i Elektronika (russ) 7, 2087 (1963); 8, 1941 (1963).
4. M. P. Southworth, Central. Engin. 11, 69 (1964).
5. D. L. Eaton, J. Amer. Ceram. Soc. 47, 553 (1964).