1. Department of Paediatric Oncology/Haematology, Erasmus MC-Sophia Children's Hospital, Rotterdam, The Netherlands.
2. Department of Palliative Care, Policy and Rehabilitation, Cicely Saunders Institute, King's College London, London, United Kingdom.
3. Princess Maxima Center for Paediatric Oncology, Utrecht, The Netherlands.
4. Faculty of Health Sciences, University of Southampton, Southampton, United Kingdom.