1. Human tonic immobility: measurement and correlates;Abrams;Depression and Anxiety,2009
2. Diagnosis and Statistical Manual of Mental Disorders;American Psychiatric Association,1994
3. Post-traumatic stress disorder after childbirth;Ballard;British Journal of Psychiatry,1995
4. Birth Choice UK, 2011. Index of National Maternity Statistics. Available from: 〈http://www.birthchoiceuk.com/Professionals/BirthChoiceUKFrame.htm?〉 〈http://www.birthchoiceuk.com/Professionals/CSHistory.htm〉 (last accessed 6 July 2011).
5. Birth Choice UK Professional, 2009. Historical Statistics: Caesarean Section. Available from: 〈http://www.birthchoiceuk.com/Professionals/BirthChoiceUKFrame.htm?〉〈http://www.birthchoiceuk.com/Professionals/NormalBirthEstimation.htm〉 (last accessed 20 December 2009).