Watt R G, McGlone P, Kay E J
Department of Epidemiology and Public Health, Royal Free and University College London Medical School, University College London, 1-19 Torrington Place, London WC1E 6BT.
Br Dent J. 2003 Jul 12;195(1):27-31. doi: 10.1038/sj.bdj.4810276.