1. Department of Epidemiology and Population Health; London School of Hygiene and Tropical Medicine; Keppel Street London WC1E 7HT U.K
2. Centre for Evidence-based Healthcare; Medizinische Fakultät Carl Gustav Carus, der Technischen Universität Dresden; Dresden Germany
3. Centre of Evidence-based Dermatology; University of Nottingham; Nottingham U.K