1. Epidemiology of anencephalus and spina bifida;Elwood, J.M.; Elwood, J.H.,1980
2. Neural tube defects;Nevin, N.C.;Lancet,1981
3. 19-Year incidence of neural tube defects in area under constant surveillance;Owens, JR, McAllister; E, Harris; F, West; L.;Lancet,1981
4. The apparently declining prevalence of neural tube defect in two counties in South Wales over three decades illustrating the need for continuing action and vigilance;Laurence, K.M.;Z Kinderchir,1985
5. Anencephaly in the Netherlands: a remarkable decline;Romijn, J.A.; Treffers, P.E.;Lancet,1983