-
First-trimester contingent screening for trisomy 21 by biomarkers and maternal blood cell-free DNA testing.
Nicolaides KH, Wright D, Poon LC, Syngelaki A, Gil MM.
Ultrasound Obstet Gynecol 2013;42:41-50. pdf -
First-Trimester Screening for Trisomy 21 Using Alpha-Fetoprotein.
Bredaki FE, Wright D, Matos P, Syngelaki A, Nicolaides KH.
Fetal Diagn Ther 2011;30:215-8.