1. J. H. Phifer, J. Appl. Polym. Sci., 2, No. 3, 1041 (1965).
2. I. N. Kotomina and A. T. Serkov, Khim. Volokna, No. 5, 71?72 (1969).
3. D. Tunk, R. Bampton, and T. E. Mueller, Tappi, 52, No. 10, 1882?1885 (1969).
4. R. A. Khurgina and A. B. Pakshver, Khim. Volokna, No. 2, 25?29 (1962).
5. Kh. Dautzenberg abd B. Filipp, Khim. Volokna, No. 5, 23?29 (1971).