Lilford Richard J, Chilton Peter J, Hemming Karla, Girling Alan J, Taylor Celia A, Barach Paul
Public Health, Epidemiology and Biostatistics, University of Birmingham, Edgbaston, West Midlands B15 2TT.
BMJ. 2010 Aug 27;341:c4413. doi: 10.1136/bmj.c4413.