de Beer, M
Vrijkotte, T G M
Fall, C H D
van Eijsden, M
Osmond, C
Gemke, R J B J
Article History
Received: 8 January 2014
Revised: 5 August 2014
Accepted: 14 October 2014
First Online: 1 December 2014
Competing interests
: The authors declare no conflict of interest.