1. M. L. Barry andP. Olsen,Solid State Technol. 11 (1968) 39.
2. Idem, J. Electrochem. Soc. Solid State Sci. Technol. 116 (1969) 258.
3. Idem, ibid. 117 (1970) 1905.
4. K. M. Mar,ibid. 126 (1979) 1252.
5. D. L. Flowers andSchyi-Yi Wu,ibid. 129 (1982) 229.