1. Ptashne, M., in The Bacteriophage Lambda (edit. by Hershey, A.), 221 (Cold Spring Harbor Laboratory, New York, 1971).
2. Maniatis, T., Ptashne, M., and Maurer, R., Cold Spring Harb. Symp. quant. Biol., 38 (in the press).
3. Pirrotta, V., Nature new Biol., 244, 13 (1973).
4. Maniatis, T., and Ptashne, M., Proc. nat. Acad. Sci. U.S.A., 70, 1531 (1973).
5. Sharpe, P. A., Sugden, B., and Sambrook, J., Biochemistry, N.Y., 12, 3055 (1973).