1. Carpenter, R. G. & Emery, J. L. Nature 250, 729 (1974).
2. Carpenter, R. G. & Emery, J. L. SIDS 1974 (ed. Robinson, R. R.) 91–96 (Canadian Foundation for the Study of Infant Deaths, Toronto and London, 1974).
3. Hughes, E. Practitioner 192, 534 (1964).
4. Alberman, E. D. & Goldstein, H. Br. J. prev. soc. Med. 24, 129 (1970).
5. Knox, E. G. & Mahon, D. F. Archs Dis. Childh. 45, 634 (1970).