Frederiksen, Henrik
Farkas, Dóra Körmendiné
Horváth-Puhó, Erzsébet
Nørgaard, Jan M
Nørgaard, Mette
Sørensen, Henrik T
Article History
Received: 12 July 2016
Revised: 25 October 2016
Accepted: 3 November 2016
First Online: 29 November 2016
Competing interests
: The authors declare no conflict of interest.