1. Lin B, Wu H, Cai Z (1987) Yuanzineng Kexue Jishu 21:447
2. Ishibashi M, Kawai T (1952) Nippon Kagaku Zasshi 73:380
3. Ishibashi M, Motojima K (1952) Nippon Kagaku Zasshi 73:491
4. Motojimi K (1955) Nippon Kagaku Zasshi 76:902
5. Japan Industrial Standard (JIS) (1974) K0102