van der Heijden, Marcel G A
de Bruin, Susanne
Luckerhoff, Ludo
van Logtestijn, Richard S P
Schlaeppi, Klaus
Article History
Received: 27 February 2015
Revised: 5 May 2015
Accepted: 8 June 2015
First Online: 14 July 2015
Competing interests
: The authors declare no conflict of interest.