-
Inverted Pyramid of Care.
Sonek JD, Kagan KO, Nicolaides KH.
Clin Lab Med 2016;36:305-17. pdf -
Maternal serum inhibin-A and free beta-hCG concentrations in trisomy 21 pregnancies at 10-14 weeks of gestation.
Noble PL, Wallace EM, Snijders RJ, Groome NP, Nicolaides KH.
BJOG 1997;104:367-71.