Article History
Received: 29 November 2017
Accepted: 15 March 2019
First Online: 30 March 2019
Compliance with ethical standards
: All procedures followed were in accordance with the ethical standards of the responsible committee (The Ethics Committee of the Faculty of Arts and Social Sciences, University of Zurich). Informed consent was obtained from all participants for being included in the study. Children were informed in an age appropriate manner and signed a consent form. Parents received written information and signed the consent form.
: The authors declare that they have no conflict of interest.