American Journal of Obstetrics and Gynecology
American Journal of Obstetrics and Gynecology > 1999 > 180 > 1 Supplement 2 > S251-S256
American Journal of Obstetrics and Gynecology > 1999 > 180 > 2 > 429-434
American Journal of Obstetrics and Gynecology > 1999 > 181 > 4 > 773-779
American Journal of Obstetrics and Gynecology > 1999 > 181 > 4 > 784-788
American Journal of Obstetrics and Gynecology > 1999 > 181 > 6 > 1530-1536