Schuurman, Agnes G
van der Kolk, Dorina M
Verkerk, Marian A
Birnie, Erwin
Ranchor, Adelita V
Plantinga, Mirjam
van Langen, Irene M
Article History
Received: 6 May 2014
Revised: 2 September 2014
Accepted: 31 October 2014
First Online: 7 January 2015
Competing interests
: The authors declare no conflict of interest.