1. I. Keiji, Handbook of Polyurethane Resins (Nikkan Kosyo Shimmbun, Tokyo, 1987), Chap.1.
2. M. J. Comstock, Urethane Chemistry and Applications ACS Symposium Series (Am. Chem. Soc., Washington, 1981), Chap.1.
3. W. Meckel, W. Goyert, and W. Wieder, Thermoplastic Elastomers (Hanser Gardener Publ., New York, 1987), Chap.2.
4. J. M. Buist, Developments in Polyurethane (Appl. Sci. Publ., London, 1978), Vol.1.
5. A. J. El-Ghayoury, J. Polym. Sci., Part A: Polym. Chem. 40, 4020 (2002).