1. Department of Palliative Medicine, University Hospital Bonn, Bonn, Germany.
2. Faculty of health, School of Psychology, University of Plymouth, Plymouth, United Kingdom.
3. Department of Psychology, University of Zurich, Zurich, Switzerland.
4. Foundation “Humor Hilft Heilen” (Humor Helps to Cure), Bonn, Germany.
5. Center for Palliative Care, Helios Hospital Bonn/Rhine-Sieg, Bonn, Germany