Article History
Received: 26 February 2018
Accepted: 17 January 2019
First Online: 28 January 2019
Compliance with ethical standards
: Participation was anonymous and voluntary, and participants signed an informed consent stating the purpose and method of the study, as well as participant rights. The Ethics Committee of the University of Antwerp also approved the study.
: The authors declare that they have no conflict of interest.