1. Dayhoff, M. O. (ed.) Atlas of Protein Sequence and Structure Vol. 5 (Natn. Biomed. Res. Foundation, Silver Spring, Maryland, 1972).
2. Efstratiadis, A. et al. Cell 21, 653–668 (1980).
3. Jeffreys, A.J. in Genome Evolution (eds Dover, G. A. & Flavell, R. B.) 157–176 (Academic, London, 1982).
4. Craik, C. S., Buchman, S. R. & Beychok, S. Proc. natn. Acad. Sci. U.S.A. 77, 1384–1388 (1980).
5. Eaton, W. A. Nature 284, 183–185 (1980).