Article History
Received: 27 August 2020
Accepted: 15 November 2020
First Online: 4 December 2020
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.
: The Human Research Ethics Committee of Bern (Kantonale Ethikkommision KEK Bern, Bern, Switzerland) approved the project (KEK n° 10-10-2006 and 8-11-2006). The study was performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments.