1. Unit for Population-Based Dermatology Research; St John's Institute of Dermatology; King's College London and Guy's and St Thomas' NHS Foundation Trust; London U.K.
2. Program for Clinical Research; Department of Dermatology; University of California San Francisco (UCSF); CA U.S.A.
3. Centre for Evidence Based Healthcare; School of Health Sciences; University of Nottingham; Nottingham U.K.
4. Division of Evidence based Medicine (dEBM); Department of Dermatology, Venerology und Allergy; Charité - Universitätsmedizin Berlin; Berlin Germany
5. Dermatology Department; Leiden University Medical Centre; Leiden the Netherlands