1. X-ray pelvimetry of the pregnant adolescent. Pelvic size and the frequency of contraction;Aiman;Obstetrics & Gynecology,1976
2. Alderson P Green S Higgins JPT Medline search strategies for optimal sensitivity in identifying randomised clinical trials Cochrane Reviewers’ Handbook 4.2.2 [updated December 2003]; 11a. Appendix B. In: The Cochrane Library, Issue 1, 2004. Chichester, UK: John Wiley & Sons, Ltd
3. Forceps and vacuum delivery: a survey of North American residency programs;Bofill;Obstetrics & Gynecology,1996
4. Guidelines for operative vaginal birth;Cargill;Journal of Obstetrics and Gynaecology Canada: JOGC,2004