1. S. Okada, H. Nakahara, et al., Chem. Pharm. Bull., 35, No. 2, 761-768 (1987).
2. V. Sunel, S. Ciovica, et al., Cell. Chem. Technol., 29, No. 1, 11-15 (1995)
3. B. Philipp, W. Bock, et al., J. Polymer Sci., Polymer Symp., 66, 83-100 (1979).
4. A. D. Virnik, M. A. Penenzik, et al., Cell. Chem. Technol., 30, Nos. 1-2, 39-47 (1996).
5. C. Vasiliu-Oprea, S. Badiu, et al., Cell. Chem. Technol., 29, No. 4, 463-469 (1995).