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First-trimester maternal serum PAPP-A, SP1 and M-CSF levels in normal and trisomic twin pregnancies.
Bersinger NA, Noble P, Nicolaides KH.
Prenat Diagn 2003;23:157-62. -
Semiquantitative immunohistochemical localisation of PAPP-A and beta-hCG in first trimester chorionic villi from euploid and trisomic pregnancies.
Sebire NJ, Roberts L, Nicolaides KH.
J Pathol 2000;192:30.