1. Hardy..Proc. Roy. Soc., 1912,87 A, 29.
2. Le Blanc and Kroger..Z. Elektrochem., 1921,27, 335.
3. Prasad and Sundaram .. Part II, Communicated for publication.
4. -- .. Part III, Communicated for publication.
5. Palit and Co-workers..J. Indian Chem. Soc., 1942,19, 271; 1949,26, 12;J. Am. Chem. Soc., 1947,69, 3120;J. Am. Oil Chem. Soc., 1947,24, 190.