1. Akabori, S.: 1955,Kagaku (Science in Japanese)25, 54.
2. Morimoto, S.: 1966,Intern. Sympos. on Macromol. Chem., Tokyo, Kyoto.
3. Morimoto, S. and Ponnamperuma, C.:160th Meeting Am. Chem. Soc., Chicago, Sep (1970);
4. XXIII Intern. Cong. Pur. Appl. Chem., Boston, Jul. (1971).
5. Ponnamperuma, C. and Woeller, F.: 1968,Curr. Mod. Biol. 1, 156.