title: "Vaginal delivery of the nonvertex second twin": does this study have a type II error?
authors.forename: R
authors.initials: R
authors.lastname: Mittendorf
mesh_terms: D015982:Bias; D001946:Breech Presentation; D002585:Cesarean Section / Q000706:statistics & numerical data; D036861:Delivery, Obstetric / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D011247:Pregnancy; D011272:Pregnancy, Multiple; D014427:Twins