1. Bassi P S and Sharma I B 1972Indian J. Chem.
12 813
2. Bassi P S and Sharma I B 1972Indian J. Chem.
A15 649
3. Cabrera N and Mott N F 1949Reports on progress in physics (London: The Physical Society) Vol. 12 p. 163
4. Grimley T B 1955Chemistry of the solid state (ed) W E Garner (London: Butterworths) p. 336
5. Hardel K 1972Angew. Chem. Int. Ed. Engl.
11 173