1. “Kodapak PET, Thermoplastic Polyester” (Eastman Chemical Products Inc., Kingsport, USA, 1982).
2. W. L. Corsoever, Netherlands Patent 7 203 971 (1972)
3. US Patents 3 803 275 (1974) and 3 745 150 (1973).
4. H. G. Fritz, Kunstoffe
68 (1978) 450.
5. N. C. Wyeth and R. N. Roseveorve, US Patent 3 733 309 (1973).