1. P. D. Greene, E. L. Bush andI. R. Rawlings, Extended Abstract no. 479, The Electrochemical Society Meeting, Fall 1968, Montreal, Canada available from The Electrochemical Society, Princeton, N.J., USA).
2. R. Stratton, in ?Progress in Dielectrics?, Vol. III (edited by J. B. Birks and J. Hart) (John Wiley, New York, 1961).
3. A. K. Vijh,J. Phys. Chem. Solids 29 (1968) 2233.
4. Idem, J. Mater. Sci. 5 (1970) 379.
5. R. T. Sanderson, ?Chemical Periodicity? (Reinhold, 1960);idem, ?Inorganic Chemistry? (Reinhold, New York, 1967).