1. P von Lützau (corresponding author): Pediatric Palliative Care Centre and German Pediatric Pain Centre, Children's and Adolescents’ Hospital, Datteln and Department of Children's Pain Therapy and Paediatric Palliative Care, Witten/Herdecke University, Faculty of Health — School of Medicine, Dr. Friedrich Steiner Strasse 5, 45711 Datteln, Germany;
2. M Otto, T Hechler, B Zernikow: Pediatric Palliative Care Centre and German Pediatric Pain Centre, Children's and Adolescents’ Hospital, Datteln and Department of Children's Pain Therapy and Paediatric Palliative Care, Witten/Herdecke University, Faculty of Health — School of Medicine, Datteln, Germany;
3. S Metzing: Witten/Herdecke University, Faculty of Health — School of Nursing Science, Witten, Germany.
4. J Wolfe: Harvard Medical School, and Department of Psychosocial Oncology and Palliative Care, Dana-Farber Cancer Institute, Boston Children's Hospital, Boston, Massachusetts, USA