孕中期血清及超声筛查唐氏综合征临床意义
张萍,孟永勤,汪吉梅
Clinical significance of Combining second-trimester serum and ultrasound screening for Down’s syndrome 
ZHANG Ping,MENG Yongqin,WANG Jimei 
临床儿科杂志 . 2014, (5): 434 -437 .