van der Velde, Jorien
Opmeer, Esther M
Liemburg, Edith J
Bruggeman, Richard
Nieboer, Roeline
Wunderink, Lex
Aleman, André
Article History
Received: 23 December 2014
Revised: 4 April 2015
Accepted: 4 June 2015
First Online: 23 September 2015
Competing interests
: The authors declare no conflict of interest.