1. Banerjee, P. C.: J. Ind. chem. Soc. 19, 35 (1942).
2. Bergtheil, C. J., and R. V. Briggs: J. Soc. chem. Ind. 1906, 729.
3. Bloxam, W. P.: J. Soc. chem. Ind. 1906, 735.
4. Green, A. G., and A. E. Woodhead: J. chem. Soc. (London) 97, 2388 (1910).
5. Knecht, E.: J. Soc. Dyers Colourists 19, 169 (1903); 21, 9, 292 (1905); 25, 135 (1909); cf. Z. analyt. Chem. 49, 124 (1910).