1. Williams' obstetrics;Cunningham,2001
2. The principles and practice of obstetrics;De Lee,1924
3. Trends in the attendant, place, and timing of births, and in the use of obstetric interventions: United States, 1989-97;Curtin;Natl Vital Stat Rep,1999
4. Manual of standards in obstetric-gynecologic practice;American College of Obstetricians and Gynecologists,1965
5. Obstetric forceps;American College of Obstetricians and Gynecologists,1989