1. Hozumi S, Kitayama S, Shiraga N, Adachi T (1989) Polymer Preprint Japan 38: 3548
2. Kitayama S, Shiraga N (1991) Hyomen Kagaku Japan 12: 496
3. Maeda K, Yoshida M, Takigawa A, Ishizuka S, Tsujino T, Yamamoto (1989) Polymer Preprint Japan 38: 3554
4. Kogelnik H (1969) Bell Syst Tech J. 48: 2909
5. Ohno T, Kawamura K, Ueda M, Ohshima T, Okita T (1989) Polymer Preprint Japan 38: 3551