Back to matchesWe found a matchYour institution may have rights to this item. Sign in to continue.TitleSecond-trimester maternal serum free-β-human chorionic gonadotropin and α-fetoprotein levels in normal twin and singleton pregnancies: a report of local Chinese population.AuthorsXie, Zhenwei; Lu, Shiming; Zhu, Yuning; Sun, Yali; Jin, YuPublicationPrenatal Diagnosis, 2008, Vol 28, Issue 8, p735ISSN0197-3851Publication typeArticleDOI10.1002/pd.2048