1. T. Yamagata , S. Miyata and A. Nakagawa , Jpn. Patent JP 61 189 216, August 22 , 1986 ; CA , 10623298z .
2. Asahi Denka Kogyo K.K.Ajinomoto Co. Inc. Jpn. Patent JP 59 48 414, March 19 , 1984 , CA , 10112203K .
3. A Imamura and T. Konodo , Jpn. Patent JP 63 280 005, November 17 , 1988 ; CA , 11163772j .