-
Fetal right ventricular contraction and relaxation times at 11-13 weeks' gestation by speckle tracking imaging.
Persico N, Fabietti I, Baffero G, Fedele L, Nicolaides KH.
Ultrasound Obstet Gynecol 2014;43:284-90. pdf -
Screening at 11-13+6 weeks' gestation.
Sonek JD, Nicolaides KH, Janku P.
Ceska Gynekol 2012;77:92-104.