1. Correlations of malformation frequency with environmental and genetic attributes in man;Leck, I.,1977
2. Ethnic differences in the prevalence of anencephaly and spina bifida in Boston, Massachusetts;Naggan, L.; MacMahon, B.;N Engl J Med,1967
3. Ethnic differences in the incidence of malformations following migration;sLeck I;Br J Prev Soc Med
4. Anencephaly and spina bifida in the province of Quebec;Horowitz, I.; McDonald, A.D.;Can Med Assoc J
5. Environment and Birth Defects;Wilson, J.G.,1973