1. Antcnatal screenling for Down's syndrome;Wald, N.J.; Kennard, A.; Densem, J.W.; T', Chard; Butler, L.;BAIJ,1992
2. Biochemical screening;Wald, N.; Caickle, H.,1992
3. Improved performance in a prenatal screening programme for D)own's syndrome inicorporating serum-free hCG subunit analyses;Rvall, R.G.; Staples, A.J.; Robertson, E.F.; Pollard, A.C.;PrenatDiagn,1992
4. Free beta human choriogoniadotropin in Down's syndrome screening: a multicentre study of its role compared with other biochemical markers;Spencer, K.; Miallard, Coombes E.J.; AS, Milford Ward; A.,1992
5. First trimester maternal serum alpha-fetoprotein and chorionic goniadotrophin in ancuploid pregnancies;FS, Johnson A.Cowchock; M, Darbv; R, Wapner; LG, Jackson;Prenat Diagn,1991