-
First trimester urine free beta hCG, beta core, and total oestriol in pregnancies affected by Down's syndrome: implications for first-trimester screening with nuchal translucency and serum free beta hCG.
Spencer K, Noble P, Snijders RJ, Nicolaides KH.
Prenat Diagn 1997;17:525-38. -
Early prenatal diagnosis of triploidy.
Jauniaux E, Brown R, Snijders RJ, Noble P, Nicolaides KH.
Am J Obstet Gynecol 1997;176:550-4.