1. The Information Centre, Community Health Statistics. NHS Maternity Statistics, England: 2004–05. London: The Information Centre. ISBN: 1-84636-056-0. Available at http://www.ic.nhs.uk/pubs/maternityeng2005/maternitystats06/file, accessed 25 February 2007.
2. Instrumental extraction in 2002 in the ‘AURORE’ hospital network: incidence and serious neonatal complications;Dupuis;Gynecol Obstet Fertil,2003
3. The Royal Australian and New Zealand College of Obstetricians and Gynaecologists. College Statement No. C-Obs 16 Instrumental vaginal delivery. November 2006 Available at http://www.ranzcog.edu.au/publications/statements/C-obs16.pdf accessed 25 February 2007.
4. Operative vaginal delivery – year 2000;Hankins;Am J Obstet Gynecol,1996
5. Cargill YM, MacKinnon JC. Society of Obstetricians and Gynaecologists of Canada (SOGC). Clinical Practice Guidelines No. 148. Guidelines For Operative Vaginal Birth. Available at http://www.sogc.org/guidelines/public/148E-CPG-August2004.pdf. accessed 1 March 2007.