4Copel J, Pilu G, Green J, et al. Fetal echocardiographic screening for congenital heart disease: the importance of the four chamber view[J]. Am J Obstet Gynecol, 1987,157 : 648 - 655.
5Sharland GK, Allan LD. Screening for congenital heart disease prenatally: result of a 2 and 1/2 year study in the sound east thames region[J]. Br J Obstet Gynecol, 1992,99:220 - 225.
6Allan L. Antenatal diagnosis of heart disease[ J ]. Heart, 2000, 83 : 367 - 370.