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;