TY  - RPRT
TI  - Sequential and contingent prenatal screening for Down syndrome.
AU  - Nicholas J Wald
AU  - Alicja R Rudnicka
AU  - Jonathan P Bestwick
PY  - 2006
DO  - 10.1002/pd.1498
UR  - https://pubmed.ncbi.nlm.nih.gov/16821246/
ID  - 16821246
ER  -