1. Blondel B Kermarrec M Enquête Nationale Périnatale 2010 http://www.drees.sante.gouv.fr/les-naissances-en-2010-et-leur-evolution-en-2003,9625.html
2. Health and Social Care Information Centre Hospital Episode Statistics: NHS Maternity Statistics 2012-13 http://www.hscic.gov.uk/catalogue/PUB12744
3. Canadian Institute for Health Information Inpatient Hospitalizations, Surgeries and Childbirth Indicators in 2013-2014 https://secure.cihi.ca/free_products/CAD_Hospitalization%20and%20Childbirth_Infosheet_ENrev-web.pdf
4. Epidural and spinal anesthesia use during labor: 27-state reporting area, 2008;Osterman;Natl Vital Stat Rep,2011
5. Epidural abscess complicating epidural anesthesia and analgesia. An analysis of the literature;Kindler;Acta Anaesthesiol Scand,1998