- Correspondence to Emelie Thern, Child and Adolescent Public Health Epidemiology Unit, Department of Public Health Sciences, Karolinska Institutet, Tomtebodavägen 18A, Widerströmska huset, Stockholm 171 77, Sweden;
- Received June 29, 2016
- Revised November 23, 2016
- Accepted December 29, 2016
- First published January 13, 2017.
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