1. Institute of Psychology, University of Bern, Bern, Switzerland
2. National Centre of Competence in Research, Affective Sciences, University of Geneva, CISA, Geneva, Switzerland
3. Philipps University of Marburg, Marburg, Germany
4. Institute for Evaluative Research in Orthopaedic Surgery, University of Bern, Bern, Switzerland
5. Spine Center, Schulthess Klinik, Zurich, Switzerland