1. Proceedings of the 1960 Symposium on Continuous Culture of Microorganisms (SCI, London, 1961), SCI Monogr., 12, p. 21.
2. Proceedings of the 6th International Symposium on Continuous Culture of Microorganisms (Ellis Horwood, Chichester, 1976), p. 1.
3. U. S. Patent 4,018,859 (1977).