1. Intrapartum sonography and persistent occiput posterior position: A study of 408 deliveries;Gardberg;Obstet Gynecol,1998
2. Influence of persistent occiput posterior position on delivery outcome;Fitzpatrick;Obstet Gynecol,2001
3. Williams Obstetrics;Cunningham,2005
4. Malpresentations;Lanni,2007
5. Low concentrations of maternal thyroxin during early gestation: A risk factor of breech presentation?;Pop;Br J Obstet Gynaecol,2004