Chong Yap-Seng, Kwek Kenneth Y C
Department of Obstetrics and Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore 119074.
Lancet. 2010 Feb 6;375(9713):440-2. doi: 10.1016/S0140-6736(10)60055-4. Epub 2010 Jan 11.