1. Ultrasound and amniotic fluid alpha-fetoprotein in the prenatal diagnosis of spina bifida;Allen;Obstet Gynecol,1982
2. Fetal anomaly scan potentially will replace routine AFAFP assays for the detection of neural tube defects;Kooper;Prenat Diagn,2007
3. Amniotic-fluid alpha-fetoprotein measurement in antenatal diagnosis of anencephaly and open spina bifida in early pregnancy: second report of the UK collaborative study on alpha-fetoprotein in relation to neural-tube defects;Wald;Lancet,1979
4. Screening for neural tube defects in the United States: a summary of the Grough Conference;Marci;Am J Obstet Gynecol,1979
5. Ultrasound screening for spina bifida: cranial and cerebellar signs;Nicolaides;Lancet,1986