1. The nature of labor pain;Lowe;Am J Obstet Gynecol,2002
2. Great expectations: a prospective study of women's expecations and experiences of childbirth;Green,1998
3. Women's experience of pain in childbirth;Lundgren;Midwifery,1998
4. Natural childbirth the Bradley way;McCutcheon-Rosegg,1996
5. Severity of labour pain: influence of physical as well as psychologic variables;Melzack;Can Med Assoc J,1984