1. Asahi Chemical Industry Co., Ltd. (1973) Japanese Patent JP 48?60 753.
2. Buschle-Diller, G. and Zeronian, S. H. (1994)Text. Chem. Color. 26, 17?24.
3. Chisso Corporation (1981) Japanese Patent JP 56-24 430.
4. Clarkson, K. A., Larenas, E. and Weiss, G. L. (1993) U.S. Patent 5 246 853.
5. Dautzenberg, H., Loth, F., Wagenknecht, W. and Philipp, B. (1985)Das Papier 39, 601?607.