1. “Fermentation Technology Today,” ed. by G. Terni, Society of Fermentation Technology, Japan, 1972.
2. A. L. Demain, “Genetics of Industrial Microorganisms,” Vol. I, Elsevier Publishing Co., Amsterdam, 1973, p. 19.
3. S. Abe, “The Microbial Production of Amino Acids,” Kodansha Ltd., Tokyo and John Wiley & Sons, New York, 1972, p. 39.