1. C. Boshoff, Y. Takeuchi, J. D. Reeves, R. A. Weiss, Institute of Cancer Research, Chester Beatty Laboratories, London SW3 6JB, UK.
2. Y. Endo and T. Sasaki, Department of Experimental Therapeutics and Development Center for Molecular Target Drugs, Cancer Research Institute, Kanazawa University, Japan.
3. P. D. Collins and T. J. Williams, Department of Applied Pharmacology, Imperial College School of Medicine at National Heart and Lung Institute, London SW3 6LY, UK.
4. V. L. Schweickart and P. W. Gray, ICOS, 22021 20th Avenue Southeast, Bothell, WA 98021, USA.
5. M. A. Siani, Gryphon Sciences, San Francisco, CA 94080, USA.