1. K. Maurer, G. Drefahl, Ber., 75, B, 1489 (1942); 80, 94 (1947); E. Peterman, Patent C. A. 1161 F. (1951).
2. E. Degering, J. Am. Chem. Soc., 73, 840 (1951).
3. E. Jackel, W. Kenyon, J. Am. Chem. Soc., 64, 121 (1942).
4. T. Neveil, J. Text. Inst. 42, No. 3, 91 (1951).
5. G. M. Nabat, C. V. Padmanabahn, Proc. Ind. Acad., 32, sect. A, No. 1, 212 (1950).