共 13 条
[1]
BREEN JL, 1977, OBSTET GYNECOL, V49, P43
[3]
COX SM, 1988, OBSTET GYNECOL, V71, P454
[4]
FLAM F, 1991, ULTRASOUND OBST GYN, V1, P350
[8]
JAUNIAUX E, 1993, ULTRASOUND OBSTETRIC, V3, P435