title: Friedman EA. Primigravid labor: a graphicostatistical analysis. Obstet Gynecol 1955;6:567-89.
authors.forename: Roy M
authors.initials: RM
authors.lastname: Pitkin
mesh_terms: D000704:Analysis of Variance; D005260:Female; D049673:History, 20th Century; D006801:Humans; D007743:Labor, Obstetric / Q000266:history* / Q000502:physiology; D011247:Pregnancy; D014481:United States