1. Maternal serum-alpha-fetoprotein measurement in antenatal screening for anencephaly and spina bifida in early pregnancy;Lancet,1977
2. Amniotic fluid alpha-fetoprotein measurements in antenatal diagnosis of anencephaly and open spina bifida in early pregnancy;Lancet,1979
3. Open neural-tube defects;Wald,1984
4. Ultrasound in the diagnosis of spina bifida;Campbell;Lancet,1975
5. The prenatal diagnosis of fetal structural anomalies by ultrasound;Campbell;Clinics Obstet Gynaecol,1983