4Benacerraf BR. The second trimester fetus with down syndrome:detection using sonographic features. Ultrasound Obstet Gynecol, 1996,7 : 147-155.
5Baronciani D, Scaglia C, Corchia C, et al . Ultrasonography in pregnancy and fetal abnormalities: screening or diagnostic test? IPIMC 198621990 register data. Indagine Policentriea Italiana sulle Malformazioni Congenite. Prenat Diagn, 1995, 15 (12): 1101-1108.
6Ploeckinger-Ulm B, Ulm MR, Lee A, Kratochwil A, Bernaschek G. Antenatal depiction of fetal digit with threedimensional ultrasonography. Am J Obstet Gynecol, 1996,175:571-574.
7Kalache kD, Bamberg C, Proquitte H, et al. 3D Multi-slice view in evaluation of fetal anomalies. Ultrasound Med, 2006,25 : 1041- 1049.
8McHugo JM. Skeletal A, Twining P, eds. Textbook of fetal abnormalities. London: Churchill Livingstone,2000. 237-267.
9Baronciani D, Scaglia C, Corehia C, et al. Ultrasonography in pregnancy and fetal abnormalities: screening or diagnostic test?Prenat Diagn, 1995,15:1101-1108.
10Chitty CS, Hunt GH, Moore J, et al. Effectiveness of routine ultrasonography in detecting fetal abnormalities in a low risk population. BMJ, 1991,303:165-169.
