1. Department of Anesthesia, Intensive Care and Pain Therapy; University Hospital of Parma; Parma Italy
2. Foundation for Ethics in Pain Care; Bellevue Washington U.S.A.
3. Carolinas Pain Institute; Wake Forest University Baptist Health; Winston-Salem North Carolina U.S.A.
4. Department of Anesthesiology; Critical Care and Multidisciplinary Pain Center; ZOL; Genk Belgium
5. Research Unit of Molecular Epidemiology and Institute of Epidemiology II; Helmholtz Zentrum München; Munich Germany
6. German Research Center for Environmental Health; Neuherberg Germany
7. St. Catherine Specialty Hospital; Zagreb and Zabok Croatia
8. Department of Twin Research and Genetic Epidemiology; St Thomas’ Hospital; King's College London; London U.K.
9. Department of Biomedical, Biotechnological and Translational Sciences; University of Parma; Parma Italy