1. Roberts, R. J. Crit. Rev. Biochem. 4, 123–164 (1976).
2. Scheller, R. H., Dickerson, R. E., Boyer, H. W., Riggs, A. D. & Itakura, K. Science 196, 177–180 (1977).
3. Messing, J., Gronenborn, B., Muller-Hill, B. & Hofschneider, P. H. Proc. natn. Acad. Sci. U.S.A. 74, 3642–3646 (1977).
4. Dickson, R. C., Abelson, J., Barnes, W. M. & Reznikoff, W. S. Science 187, 27–35 (1975).
5. Messer, W. & Melchers, F. in The Lactose Operon (eds Beckwith, J. R. & Zipser, D.) 305–315 (Cold Spring Harbor Laboratory, Cold Spring Harbor, 1970).