1. Carbrol D. Collection: Abbreviated perinatality, Ed. Masson, 2003, p.60-62.
2. Lansac J, Berger C. Obstetrics, Collection for the Practitioner, 3rd Edition, 2000.
3. Lansac J, Marret H. Practice of Childbirth, 3rd Edition. 2001;544(7):205-10.
4. Ladewing, Patricia. Nursing and Perinatal Care. 4th Ed, Saint Laurent. 2010; 1010p.
5. Brabant I. Living your pregnancy and childbirth, A happy birth, Edition Saint Martin. 2001;23(4):32-5.