1. Population Trends 18. London: Office of Population Censuses and;Anonymous;Surveys,1979
2. Chamberlain G, Philipp E, Howlett B, Masters K. British Births 1970, vol. II: Obstetric Care. London: Heinemann Medical, 1978: 8-53.
3. Infants of very low birth weight I: perinatal factors affecting survival;Stanley, F.; Alberman, E.D.;Dev Med Child Neurol; 20: 300-12. 4Anonymous. Caring for babies of very low birth weight,1978
4. Infant and Perinatal Mortality;Monitor, 276-80. OPCS,1979
5. The week;Chamberlain, R.,1970