1. Department of Health Services Research and Nursing Science; School of Public Health, Bielefeld University; Bielefeld Germany
2. Department of Geriatrics; Parc de Salut Mar; Barcelona Spain
3. Physical Medicine and Rehabilitation (MFRHB); Hospital de la Santa Creu i Sant Pau; Barcelona Spain
4. Institute of Health and Nursing Sciences; Martin Luther University Halle-Wittenberg; Halle (Saale) Germany