Berentzen, N E
van Rossem, L
Gehring, U
Koppelman, G H
Postma, D S
de Jongste, J C
Smit, H A
Wijga, A H
Article History
Received: 5 May 2015
Revised: 21 July 2015
Accepted: 7 September 2015
First Online: 23 September 2015
Competing interests
: The authors declare no conflict of interest.