Department of Psychology and Sports, University of Bielefeld, Bielefeld, Germany;
Faculty of Science, Department of Psychology, University of Tuebingen, Tuebingen, Germany;
Department of Epidemiology, Health Monitoring, Robert Koch-Institute, Berlin, Germany;
Department of Internal Medicine VI: Psychosomatic Medicine and Psychotherapy, University Hospital Tuebingen, Germany;
Sleep; Duration; Infants; Children; Adolescents; Sleep; Problems;