1. Labour pain: the role of childbirth education, information and expectation;Astbury,1980
2. Natural childbirth a review and analysis;Beck;Obstetrics and Gynecology,1977
3. Efficacy of education in childbirth;Bergstrom-Walan;Journal of Psychosomatic Medicine,1963
4. Obstetric and psychological effects of psychoprophylactic preparation for childbirth;Charles;American Journal of Obstetrics and Gynecology,1978
5. Effects of childbirth preparation;Cogan;Clinical Obstetrics and Gynecology,1980