1. Racial variations in maternal serum alpha-fetoprotein;Shapiro;Lancet,1975
2. Racial differences in maternal serum alpha-fetoprotein;Macri;Lancet,1976
3. Prenatal diagnosis of neural tube defects IV: Maternal serum alpha-fetoprotein screening;Milunsky;Obstet Gynecol,1979
4. Alpha-fetoprotein concentrations in maternal serum: Relation to race and body weight;Crandall;Clin Chem,1983
5. Racial differences in maternal serum alpha-fetoprotein screening;Johnson,1985