1. Statistical methods in medical research;Armitage,1971
2. Environmental and obstetrical factors in prematurity;Baird;WHO Bull.,1962
3. Perinatal Problems;Baird,1969
4. Perinatal Problems;Butler,1969
5. The incidence of pre-eclamptic toxaemia in smokers and non-smokers;Duffus;Lancet,1968