1. K. Kato, J. Electron Microscopy, l4, (3), 219 (1965); Polymer Letters, b, 35 (1966).
2. K. Kato, Japan Plastic, 2, (2), 6 (1968).
3. M. Matsuo, Japan Plastics, 2, (3), 6 (1968).
4. JP-42-19248, 42- 22541 and BE-719,425
5. C. B. Bucknall, R. R. Smith, Polymer, Lond. 6, 437 (1965).