1. Besson, A., Compt. Rend., 152, 1850 (1911).
2. Bredig, G., Koenig, A., and Wagner, O. H., Z. Phys. Chem., 139 A, 211 (1928).
3. Devins, J. C., and Burton, M. J., J. Amer. Chem. Soc., 76, 2618 (1954).
4. Brit. Pat. 948,772; 958,776–8; 966,406 (1964).
5. Ouchi, A., J. Electrochem. Soc. Japan, 17, 285 (1949); ibid., 20, 164, 168, 378 (1952).