Received: 2 October 2018
Accepted: 19 February 2019
First Online: 4 March 2019
Ethics approval and consent to participate
: According to the Swiss Human Research Act [CitationRef removed] this study type in Switzerland does not require ethical approval from a cantonal ethics committee. Formal informed consent was therefore not necessary but all participants were informed either via telephone by the first author or with a short information text about the aim and content of the survey. Participants consented verbally at the telephone or via email if they wanted to participate in the study. Participation was at any point voluntary.
: Not applicable.
: The authors declare that they have no competing interests.
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