1. Department of Social Medicine, Occupational and Environmental Dermatology; University of Heidelberg; Thibautstraße 3 69115 Heidelberg Germany
2. Department of Occupational and Environmental Dermatology; University Hospital Malmö; S-20502 Malmö Sweden
3. Department of Epidemiology; Istituto di Ricerche Farmacologiche Mario Negri; IRCCS; Milan Italy
4. Department of Dermatology; Azienda Ospedaliera papa Giovanni XXIII, Bergamo; Centro Studi GISED - FROM Presidio Ospedaliero Matteo Rota; Via Garibaldi 13/15 24122 Bergamo Italy
5. Occupational and Environmental; Dermatology Unit; State University Hospital; P.O. Box 30.001 NL-9700 RB Groningen the Netherlands
6. Klinik für Dermatologie und dermatologische Allergologie; Klinikum der FSU Jena; Erfurter Str. 35 D-07740 Jena Germany
7. Clinica de Dermatologia; Hospital da Universidade Praceta Motal Pinto; Rua Infanta D.Maria; n 30-A-3D P-3000-075 Coimbra Portugal
8. Department of Dermatology; University Hospital Malmö; S-20502 Malmö Sweden