1. K.Kamide, and Y.Miyakawa, Makromol. Chem.,179, 359(1978)
2. F.L.Tobiason, C.C.Chandler, and F.E.Schwarg, Macromolecules,5, 321(1972)
3. E.Imoto, Kogyo Kagaku Zasshi,52, 188(1949)
4. T.Shono, ibid56, 422(1953)
5. S.Ishida, R.Hochin, Y.Nakamura, Y.Nakamoto, and K.Kaneko, Netsukokasei Jushi,6, 127(1985)