Sasaki A, Sawai H, Masuzaki H, Hirahara F, Sago H : Low prevalence of genetic prenatal diagnosis in Japan. Prenat Diagn. Oct 2011 ; 31 (10) ; 1007-1009
Palomaki GE, Kloza EM, Lambert-Messerlian GM, et al. ; DNA sequencing of maternal plasma to detect Down syndrome : an international clinical validation study. Genetics in medicine Nov 2011 ; 13 (11): 913-920