2[2]Andrew Edwards,Lesleigh S,Baker,et al.Changes in umbilical artery flow velocity waveforms following maternal administration of betamethasone[J].Placenta,2003,24:12-16.
3[3]Riza M,Seyfettin U,Vildan O.Doppler assessment of umbilical artery,thoracic aorta and middle cerebral artery in the management of pregnancies with growth restriction[J].Acta Obstetricia et Gynecologica Scandinavica.2001,80(8):702-707.
