1. Division of Adolescent Medicine, Indiana University, Indianapolis, USA
2. Department of Psychiatry and Psychology, Mayo Clinic School of Medicine, Rochester, USA
3. Department of Pediatrics and Adolescent Medicine, Mayo Clinic School of Medicine, Rochester, USA
4. Department of Pediatrics, University of Minnesota, Minneapolis, USA
5. Department of Human Development and Family Sciences, University of Connecticut, Storrs, USA
6. Division of Epidemiology and Community Health, University of Minnesota, Minneapolis, USA