1. M. A. Eisenberg, in “Annals of the New York Academy of Sciences,” Vol. 447, ed. by K. Dakshinamurti and H. N. Bhagavan, The New York Academy of Sciences, New York, 1985, pp. 335–348.
2. O. Ifuku, S. Haze, J. Kishimoto, T. Sakamoto, and M. Yanagi, Japan Kokai Tokkyo Koho, 61202686 (Sep. 8, 1986).
3. O. Ifuku, S. Haze, T. Sakamoto, and J. Kishimoto, Japan Kokai Tokkyo Koho, 62155081 (Jul. 10, 1987).
4. S. Haze, O. Ifuku, and J. Kishimoto, EP-A-O 316229 (May 17, 1989).