1. Gels as size selective extraction solvents
2. 2) Flory, P. J.: “Principles of Polymer Chemistry,” Cornell University Press, Ithaca (1953).
3. 3) Hanai, T.: “Mambrane and Ion” (Japanese), Chap. 6, Kagaku Dojin (1980).
4. 4) Masuda, F.: “Super Absorbent Gel” (Japanese), Kyouritsu Shuppan (1987).