Wapner, Ronald, Thom, Elizabeth, Simpson, Joe Leigh
et al. (2004). First-Trimester Screening for Trisomies 21 and 18
.
OBSTETRICAL & GYNECOLOGICAL SURVEY, 59(3), 177-179. 10.1097/01.ogx.0000115850.05556.bc
Wapner, Ronald, Thom, Elizabeth, Simpson, Joe Leigh et al. (2004). First-Trimester Screening for Trisomies 21 and 18
. OBSTETRICAL & GYNECOLOGICAL SURVEY, 59(3), 177-179. 10.1097/01.ogx.0000115850.05556.bc