1. T. Hiramatsu, S. Azuma, K. Nakagawa and Y. Ichikawa, Teijin Ltd., Japan Kokai Tokkyo Koho,
2. Japan Patent 62,263,163 (1988)
3. Chem. Abstr., 109, 73473 (1988).
4. W. Lunkenheimer and K. H. Buechel, Bayer AG, German Offen DE 2,342,724 (1975)
5. Chem. Abstr., 82, 156379 (1975).