1. Department of General and Visceral Surgery; Medical Center-University of Freiburg; Freiburg im Breisgau Germany
2. Faculty of Medicine; University of Freiburg; Freiburg im Breisgau Germany
3. Center for Medical Biometry and Medical Informatics; Medical Center-University of Freiburg; Freiburg im Breisgau Germany
4. Institute of Nursing Science; Department Public Health; University of Basel; Basel Switzerland
5. Academic Center of Nursing and Midwifery; Department Public Health and Primary Care; KU-Leuven Belgium