title: Classic pages in obstetrics and gynecology. The measurement of placental permeability with radioactive sodium. The relation of placental permeability to fetal size in the rat (Louis B. Flexner and Richard B. Roberts).
mesh_terms: D000818:Animals; D005260:Female; D049673:History, 20th Century; D008431:Maternal-Fetal Exchange; D009774:Obstetrics / Q000266:history*; D011247:Pregnancy; D051381:Rats; D012975:Sodium Isotopes; D014481:United States
chemical_list: D012975:Sodium Isotopes