Penttilä I.M., Puhakainen E. and Ryynänen M. 1990. Selecting a Sensitive Immunoradiometric Method of Maternal Serum Alphafetoprotein for Prenatal Screening of Abnormalities in the Fetus. Upsala Journal of Medical Sciences. 95, 3 (Sep. 1990), 287-290. DOI:https://doi.org/10.3109/03009739009178605.