6Shipp TD, Benacerraf BR. Second trimester ultrasound screening for chromosomal abnormalities. Prenat Diagn, 2002, 22(4):296-307.
7Raniga S, Desai PD, Parikh H. Ultxasonographic soft markers of aneuploidy in second trimester: Are we lost? Med Gen Med, 2006, 8(1):9.
8DeVore GR. The genetic sonogram: its use in the detection of chromosomal abnormalities in fetuses of women of advanced maternal age. Prenat Diagn, 2001, 21 (1) :40-5.
9DeVore GR, Romero R. Genetic sonography: an option for women of advanced maternal age with negative triple-marker maternal serum screening results. J Ultrasound Med, 2003, 22(11): 1191-9.
10Daniel A, Athayde N, Ogle R, et aL Prospective ranking of the sonographic markers for aneuploidy: data of 2143 prenatal cytogenetic diagnoses referred for abnormalities on ultrasound. Aust N Z J Obstet Gynaecol, 2003, 43(1): 16-26.