- Correspondence to Stine Schou Mikkelsen, National Institute of Public Health, University of Southern Denmark, Øster Farimagsgade 5A, 2nd floor, Copenhagen K 1353, Denmark;
- Received December 6, 2013
- Revised April 23, 2014
- Accepted May 27, 2014
- First published June 16, 2014.
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