1. I. G. Austin, N. E. Mott, Adv. in Phy. 18 41–102 (1969).
2. J. B. Goodenough, “Prog, in Sol. St. Chem.” 5 145–400 Pergamon Oxford, (1971).
3. F. S. Galasso, “Structure, Properties and Preparation of Perovskite-type Compounds” Pergamon, Oxford (1971).
4. D. B. Meadowcroft, Brit. J. Appl. Phy. Ser. 2 2 1225 (1969).
5. D. B. Meadowcroft, Nature 226 847–848 (1970).