1. Abe, M., Tabuchi, T., Tanaka, M. (1970). Nippon Nogeikagaku Kaishi 44, 493?498
2. Ajinomoto (1968). Japanese Patent No. 13939
3. Akiyama, S., Suzuki, T., Sumino, Y., Nakao, Y., Fukuda, H. (1972). In: Fermentation Technology Today. Proceedings of the IVth International Fermentation Symposium, Kyoto, 1972, G. Teruy, ed., pp. 613?617, Osaka
4. Dubowski, K.M. (1962). Clin. Chem. 8, 215?235
5. Hattori, K., Yokoo, S., Imada, O. (1974). J. Ferment. Technol. 52, 542?550